- Analog Computing, 2nd Edition
A comprehensive 460-page academic textbook covering the history, theory, and practice of analog computing from mechanical devices (Antikythera mechanism, slide rules, differential analysers) through classic electronic analog computers to hybrid and digital differential analyser systems. The book addresses basic computing elements (op-amps, integrators, summers, multipliers, function generators), programming techniques including scaling and partial differential equations, and an extensive survey of real-world applications spanning aerospace, nuclear engineering, biology, economics, and the arts. A final chapter covers the decline of analog computing in the late 1970s and its anticipated renaissance in low-power computing, AI, and high-performance computing.
- The Unbelievable Zombie Comeback of Analog Computing
A long-form WIRED feature article (May 2023) by Charles Platt examining whether analog computing is experiencing a genuine renaissance. The article surveys historic analog devices, interviews researchers at Mythic, IBM, Columbia University (Yannis Tsividis, Glenn Cowan, Ning Guo), and MIT (Sara Achour), and traces the development of chip-scale hybrid analog-digital computers such as the HCDC. It concludes that energy efficiency demands from AI workloads—where the human brain operates on approximately 20 W versus megawatts for digital equivalents—are the primary driver for renewed interest, and that differential-equation fluency will be a key skill for any analog computing revival.
- Electronics Fun & Fundamentals: Analog Reborn
A Make: magazine article by Charles Platt introducing analog computing concepts through a simple DIY project called EASY (Elementary Analog SYstem), derived from the 1961 General Electric EF-140 kit. The project uses three potentiometers and a multimeter to perform basic analog multiplication, division, and square root operations. The article also discusses the resurgence of analog computing, referencing Anabrid GmbH's educational product THAT (The Analog Thing) and the historical context of analog computers in aircraft simulation.
- Analog Computer Prototyping for the Future
Master's thesis from Malmö University (2022) documenting the design and construction of a low-cost modular single-board analog computer capable of solving second-order differential equations. The project follows design science research methodology (DSRM) and evaluates two hardware revisions (V1 and V2) through demonstration problems including Mathieu's differential equation and a spring-mass damping system. The paper argues that accessible analog and hybrid analog-digital systems are a viable path toward more energy-efficient future computing.
- A Survey on Analog Models of Computation
A comprehensive academic survey covering analog models of computation from both the historical 'computing by analogy' and the mathematical 'working on the continuum' perspectives. The paper systematically classifies models (GPACs, neural networks, BSS machines, hybrid systems, reaction-diffusion systems, population protocols, and more) along discrete/continuous time-space axes, with emphasis on computability and complexity theory. Published as a chapter in the Springer Handbook of Computability and Complexity in Analysis (2021); arXiv preprint 1805.05729.
- Understanding Operational Amplifier Specifications
A Texas Instruments application report (SLOA011B, revised July 2021) by Jim Karki that explains how to interpret operational amplifier data sheet specifications. The document covers the ideal op amp model, non-inverting and inverting amplifier topologies, a simplified internal circuit diagram, and a detailed treatment of seventeen key parameters including input offset voltage, bias current, common-mode rejection ratio, slew rate, gain-bandwidth product, noise, THD+N, and settling time. It is intended to help engineers select op amps by understanding what published specifications mean and how TI defines and tests each parameter.
- Analog and Hybrid Computer Programming
A comprehensive textbook by Prof. Dr. Bernd Ulmann covering the theory and practice of programming analog and hybrid computers, from foundational computing elements (summers, integrators, multipliers, potentiometers, comparators) through basic and advanced programming techniques, special functions, and a wide range of application examples including chaotic attractors, celestial mechanics, and partial differential equations. All worked examples are implemented on the Analog Paradigm Model-1, with discussion of how setups translate to classic EAI and Telefunken machines. The book also addresses hybrid computer architectures that couple analog and digital processors, and includes appendices on Laplace transforms and operational calculus.
- Rechenanlage "Verograph" zur genauen, laufenden Distanzbestimmung — Früher elektrischer Analog-Rechner
A 28-page technical-historical study (December 2018) by André Masson examining the Contraves AG "Verograph" system, an early electrical analog computer developed from ~1936 for continuous real-time aircraft range determination using two theodolites spaced 1–2 km apart and resistance-network computing elements operating at 75 Hz AC. The article reconstructs the sine-rule geometry, the two-stage coordinate transformation that reduces uniform precision errors across the sky, and the Wheatstone-bridge-based resistance-selector technique used in place of amplifier tubes. The companion "Stereomat" device (same technology, post-hoc 3-D shell-burst error computation) is also introduced, and Fritz Fischer's role as Contraves founder and chief inventor is documented.
- AD633-EP Low Cost Analog Multiplier
Datasheet for the AD633-EP, a functionally complete four-quadrant analog multiplier IC in an 8-lead SOIC package, specified over the -55°C to +125°C military temperature range. The device implements the transfer function W = (X1-X2)(Y1-Y2)/10V + Z, with laser-trimmed total accuracy within 2% of full scale, 1 MHz bandwidth, 20 V/µs slew rate, and supply voltages from ±8 V to ±18 V. Applications covered include multiplication, division, squaring, modulation/demodulation, phase detection, and voltage-controlled amplifiers and filters.
- ADC Voltage Reference Buffer Optimization Reference Design for High-Performance DAQ Systems
This Texas Instruments reference design (TIDA-01055, document TIDUDE2A) presents an optimized two-stage composite voltage reference buffer for driving the REF pin of an 18-bit, 2-MSPS SAR ADC (ADS9110) in high-performance DAQ systems. The design uses a REF5040 4.096 V reference combined with an OPA378 precision op-amp and an OPA837 high-speed op-amp in a composite configuration, achieving a system ENOB of 15.77 bits at 1.94 W total power—a 22% power improvement over the conventional OPA625-based approach. The document covers stability, noise, power, and transient analysis via TINA-TI simulation, hardware jumper configuration, PCB layout recommendations (thick versus thin trace comparison), and measured performance results across multiple buffer and reference options.
- Mechanische Rechner der Fliegerabwehr, frühe Lösungen: Flugzeugvermessung im 1. Weltkrieg und danach, ca. 1915–1936
A 34-page German-language research article by André Masson (October 2017) examining early mechanical fire-control instruments for anti-aircraft defense from roughly 1915 to 1936. The article covers the Auswanderungsmesser 17 (lateral deviation meter) and its associated command disc used to compute shell lead angles, a patented Swedish triangulation device (Reich Patent 374514, 1917), an early mechanical angular-velocity/lead-angle calculator (Reich Patent, January 1917), and Swiss experiments with a 7.5 cm Krupp gun on a rotating tower mount. It analyses the geometry of the instruments, identifies unresolved puzzles in the eyepiece grid design of the AM 17, and discusses why these WWI-era devices were still being manufactured under Nazi-era production codes in the early 1940s.
- Frühe Flugzeugvermessung durch mechanische Rechner bei der Fliegerabwehr: Kurvenflug-Rechner
The eighth in a series of articles by André Masson on mechanical anti-aircraft fire-control computers of the Second World War era. The article examines the challenge of curved-flight extrapolation in mechanical fire-control predictors, presenting the 1935 Fischer 'Denkschrift' and the Bandi 'Memorial Luftschutz' as foundational documents, then describes how curved-flight calculation was eventually realized in the Swiss Gamma-Hasler 43 and the German Wehrmacht Kommandogerät 40. Also covers early Contraves devices (Oionoskop, Stereomat, Verograph) and includes a chronology of the first decade of Swiss heavy anti-aircraft defense through 1945.
- Frühe mechanische Rechner der Artillerie und Fliegerabwehr: Automatisierte Rechner für Geschossflugbahnen
A 24-page German-language historical article by André Masson (2017) examining pre-electronic mechanical analog computers used to calculate artillery and anti-aircraft projectile trajectories. The article surveys historical integrating gear mechanisms (friction-disc, cone, Amsler ball integrator, drum gear), then details two concrete devices: the Fösgen trajectory computer (Rheinmetall-Borsig / TH Aachen dissertation, 1937, possibly never built) and the Curti-Dubois-Amsler ballistic integraph 'Mariandl' (built 1948 by Amsler & Cie. Schaffhausen for the Swiss Army, later rebuilt). Appendices cover pre-electronic muzzle-velocity measurement, a chronology of the Curti device development through 1956, and unresolved technical questions.
- Design and Analysis of an Analog Computer: From Concept to Final System
A 23-page student engineering paper documenting the design, construction, and analysis of a small analog computer built around operational amplifier circuits. Covers summation amplifiers, integrators, and multipliers as core building blocks, then demonstrates the system solving differential equations, and concludes with observations on the practical viability of large-scale analog computation.
- Mechanisches Rechnen mit präzis geformten Stahlkörpern und Zahnrad-Getrieben
A 2015–2016 research article by A. Masson investigating 143 negative-transparency numerical tables held at the Museum für Kommunikation, Bern, which document HASLER's ballistic cam-body (Formkörper) calculations prepared for the Italian anti-aircraft gun 90/53 circa 1950–1951. The article describes the operating principle of three-dimensional cam bodies and gear mechanisms in mechanical fire-control computers (GAMMA-JUHASZ and GAMMA-HASLER), analyzes whether the five sets of tables correspond to known Swiss HASLER command instruments, and includes appendices on air resistance, ball integrators, and the chronological development of HASLER devices.
- Kommandogerät der Fliegerabwehr mit vereinfachter Geometrie, 1938–1950: Ein sog. "Winkelgeschwindigkeits-Gerät"
An 11-page German-language technical article by André Masson (2016) describing the simplified angular-velocity fire-control computer (Kommandogerät) developed by the Swiss Federal Arms Factory W+F and manufactured by HASLER AG for the 34 mm anti-aircraft cannon from 1938. The article details the mechanical gear train, cam bodies, stepped-gear angular-velocity input, telephone-impulse-technique (TIT) data transmission to the guns, and manual correction mechanisms, along with a chronology of the device's operational use in Switzerland (1938–1942) and its eventual replacement. This is the fifth in a series of articles by the same author on WWII-era Swiss anti-aircraft mechanical analog computers.
- Wirkungsweise des ungarischen Kommandogerätes GAMMA-JUHÁSZ
A detailed 28-page technical study (Winter 2014/15) by André Masson describing the design and operation of the Hungarian GAMMA-JUHÁSZ mechanical analog fire-control computer, which was adopted by Switzerland from 1937 and built under license by HASLER. The document covers the machine's geometric (non-Cartesian) computation principle, its ~400 kg gear-train architecture, form-body nonlinear function generators, electrical servo-tracking (micrometer) circuits, speed measurement subsystems, and successive model variants (Kgt. 38, 40, 43, 50), comparing the GAMMA-JUHÁSZ approach with the competing SPERRY system.
- AD633 Low Cost Analog Multiplier Data Sheet
Complete datasheet (Rev. K, 2015) for the Analog Devices AD633, a functionally complete four-quadrant analog multiplier IC available in 8-lead PDIP and SOIC packages. The transfer function is W = (X1-X2)(Y1-Y2)/10V + Z, with 1 MHz bandwidth, 20 V/µs slew rate, and laser-trimmed total error within 2% of full scale; supply voltages range from ±8 V to ±18 V. The document covers electrical specifications, pin configurations, functional description, error sources, and application circuits including squaring, frequency doubling, division, square rooting, variable scale factor, amplitude modulation, voltage-controlled low-pass and high-pass filters, quadrature oscillator, AGC amplifiers, and SPICE simulation examples in Multisim, PSPICE, and SIMetrix.
- EAI TR-48 Analog Computer Module Configuration on York University Computer, As Built for Installed Board
A single large-format schematic drawn to scale by Josh Bensadon (September 5, 2012, revised October 10, 2012) documenting the module configuration and patch panel layout of an EAI TR-48 analog computer as installed at York University. The drawing identifies each installed module bay (amplifiers, attenuators, multipliers, and patch connections) with shunt types keyed by EAI part numbers (005-172 through 005-174) and resistor values ranging from 100K to 10M ohm at 1% tolerance. Revision notes record corrections to wiring for a board that came pre-installed and minor fixes to module naming and labels.
- EAI TR-48 Analog Computer -8V / 2V Power Supply Schematic
A single-page vector schematic depicting the -8V and 2V power supply circuit of the EAI TR-48 analog computer, drawn by Josh Bensadon on October 10, 2012. The diagram shows a transformer (T1) with 24-ohm secondary windings, rectifier diodes (D1, D2), filter capacitors (C1, C2), fuses (F1 3A, F2 0.5A), a 2N1218 transistor regulator, a zener diode reference (-1.8V, 100mW), and a 22-pin Amphenol connector providing -8V, -8V return, 2V, 2V return, and 2V control outputs; AC input provisions for both 120VAC and 240VAC are shown. A top-view component placement inset is included.
- OP07 Ultralow Offset Voltage Operational Amplifier Data Sheet
Datasheet (Rev. G, October 2011) for the Analog Devices OP07 ultralow offset voltage operational amplifier, covering OP07E (0°C to 70°C) and OP07C (−40°C to +85°C) performance grades. Key specifications include a maximum input offset voltage of 75 µV (OP07E), long-term VOS stability of 1.5 µV/month maximum, input noise voltage of 0.6 µV p-p (0.1 Hz to 10 Hz), open-loop gain of 200 V/mV minimum, and supply voltage range of ±3 V to ±18 V. The document provides full electrical characteristics tables, typical performance curves (gain vs. temperature, noise, CMRR, PSRR), application circuits including thermocouple amplifier, absolute-value circuit, and precision summing amplifier, package outline dimensions for 8-lead PDIP and SOIC_N, and ordering information.
- The Power of Analogs
A 37-slide presentation by Bernd Ulmann (December 2010) tracing the history of analog computing from the Antikythera mechanism (~150 BC) through Lord Kelvin, Philbrick's Polyphemus, Hoelzer's Mischgeraet, and the NASA zenith era of the 1960s–70s, then examining the technology's decline and potential future revival. Covers the fundamental approach of indirect analogies — translating differential equations into electronic circuits — and argues that FPGA- or massively-parallel-chip-based digital implementations of analog computing elements could offer superior performance for dynamic-systems simulation. Illustrated with the Lorenz attractor as a worked example.
- Demonstrations-Analogrechner mit Röhren
An 8-page German technical description (dated 21 August 2010) by F. Vogel of a small home-built vacuum-tube demonstration analog computer. The machine uses 10 tubes (4× 6U8, 3× EAA91, 3× OA2), operates at ±50 V machine unit with +300/−150 V supplies, and provides four computing amplifiers (two integrators/summers, one summer, one open amplifier/inverter), three coefficient potentiometers, a piecewise-linear diode function generator for y = −x², two free diodes, reference voltage sources, and a panel meter. Circuit design for the amplifiers is derived from the Heath EC-1 educational analog computer.
- Rechenbeispiele fur den RAR Analogrechner — Rechenbuch 1
Chapter 6 of a programming guide for the RAR small analog computer (±50 V machine voltage), presenting worked computing examples covering basic summing and integration operations, diode function generator use, first- and second-order linear differential equations (including spring-mass systems), and implementation of discontinuous functions (comparator, signum, absolute value). Each section provides the circuit configuration, governing equations, and oscillogram results. The document was created in 2010 by Oliver Bach and appears to be a self-contained workbook excerpt (Rechenbuch 1).
- Faszination Analogrechnen — Geschichte und Grundlagen elektronischer Analogrechner
A 45-slide German-language lecture presentation by Bernd Ulmann surveying the history and fundamentals of analog computing from mechanical devices (Antikythera, Kelvin tide predictor, differential analyzers) through early electronic machines (Hoelzer, fire control computers) to transistorized systems (Telefunken RA series, EAI machines), hybrid computers, digital differential analyzers, and simulation. The presentation covers computing elements, programming techniques (scaling, normalization, example problems), a broad survey of application domains, and a discussion of why analog computing declined and its potential future role in FPGAs, GPUs, and neuromorphic computing.
- Think Analog
A 65-page slide presentation delivered by Bernd Ulmann at the Humboldt University Berlin Medientheorien colloquium on 27 May 2009. The talk introduces analog computation through direct and indirect analogies, walks through worked examples (bouncing ball, Joukowski wing simulation), contrasts the structural programming model of analog computers with stored-program digital machines, and concludes with a forward-looking discussion of digital-analog hybrid architectures using FPGAs and GPUs as high-speed analog processors.
- Demonstrations-Analogrechner (DIY Miniatur-Analogrechner)
A 9-page German technical description by F. Vogel (2009) of a self-built miniature demonstration analog computer housed in a 188×120×77 mm aluminum enclosure. The machine uses BiFET op-amps with ±10 V machine units and provides 2 integrators, 3 summers, an open amplifier/inverter, 4 ten-turn coefficient potentiometers, a translinear multiplier unit (multiply, divide, square, square-root to ≤0.3% error), and a diode function generator for sine. Auxiliary features include a triangle-wave generator (1.5–75 Hz), 12-position address selector, overload indicator, and ±15 V DC/DC supply powered from a 9 V external adapter.
- MT-055 Tutorial: Chopper Stabilized (Auto-Zero) Precision Op Amps
This six-page tutorial from Analog Devices (MT-055) explains the operating principles of chopper-stabilized (auto-zero) precision op amps, covering the classic chopper architecture and the modern two-amplifier auto-zero topology used in IC implementations. It compares fixed versus pseudorandom chopping frequencies for intermodulation distortion, discusses the patented ping-pong auto-zero/chopper technique used in the AD8628/AD8629/AD8630 family, and provides noise performance data contrasting auto-zero amplifiers against precision bipolar types such as the OP177. Key design guidance notes that choppers should be selected for their ultralow offset and drift rather than their 1/f noise suppression, and that parasitic thermocouple effects in external circuitry must be avoided to realize full performance.
- Faszination Analogrechnen
Lecture presentation by Bernd Ulmann delivered at the 2008 Kolloquium zur Geschichte der Naturwissenschaften, Mathematik und Technik in Hamburg, providing a broad introduction to the history and technology of analog computers. The 132-slide presentation surveys mechanical analog computers (slide rules, planimeters, tide predictors, fire control computers, differential analyzers), early electronic analog computers including Helmut Hölzer's A4 rocket guidance work and Bell Labs fire control developments, electronic computing elements (integrators, multipliers, function generators), programming methods, example problems, and application areas, concluding with an outlook on the future of analog computing.
- Simulating a Bouncing Ball in a Box
A single-page application note by Bernd Ulmann describing how to simulate a bouncing ball in a box on an analog computer, inspired by an earlier Telefunken paper. Three subcircuits are used: one for y-position with gravity and damping via Z-diodes, one for x-position using comparators for wall reflection, and one generating a high-frequency sine/cosine pair to render a circular ball on an oscilloscope screen. The implementation runs on an RA742 analog computer in repetitive mode.
- The Telefunken RA 770 Analog Computer
A first-person account (dated December 2007) of acquiring, restoring, and documenting a Telefunken RA 770 high-precision analog computer (accuracy 10^-4, weight ~550 kg). The article describes mechanical and electrical restoration after rodent damage, and covers major subassemblies including dual power supplies, the DBG 771 digital control drawer with oven-stabilized quartz oscillator, chopper-stabilized OP14 operational amplifiers, servo potentiometers for coefficient setting, non-linear network drawers (NNT 771), variable function generators (VFG 801), and the coaxial analog patch field.
- Analog and Hybrid Computing
A 66-page slide-presentation by Bernd Ulmann (vaxman.de), dated 1 May 2006, giving a broad introduction to analog and hybrid computing. It progresses from early mechanical analog devices (slide rules, planimeters, differential analyzers) through electronic analog computer fundamentals and on to hybrid digital–analog systems, covering core computing elements, programming techniques, and practical problem-solving examples.
- Workshop – Analog Computing
Slide deck from the 'Analog Computing' workshop held at VCFE-2006 in Munich, presented by Bernd Ulmann. Covers hands-on analog computer programming through three worked examples of increasing complexity: a mass-spring-damper system, Volterra predator-prey (rabbit-lynx) coupled differential equations, and a bouncing ball in a box with elastic reflections, friction, and gravity. All examples were patched and run on real Telefunken RA741/RA742 hardware; circuit diagrams, scaling considerations, and oscilloscope output photos are included throughout.
- Telefunken Analog and Hybrid Computers
A 57-page illustrated presentation by Bernd Ulmann (April 2006) tracing the complete history of Telefunken analog and hybrid computers from the 1955 tube-based prototype through the late-1970s RA770. Covers computing elements, circuit design choices (drift compensation, parabola multipliers), and successive production machines including the RA463, RAT700, RA770, RA775, RA800H, and the HKW900 hybrid coupler unit. Intended as a historical survey and preservation appeal, with photographs of surviving hardware and references to primary Telefunken documentation.
- The TELEFUNKEN RA 741 Analog Computer
A first-person restoration account of a TELEFUNKEN RA 741 analog computer, originally rescued from the University of Aachen. The article details repair of the power supply (including the ±10 V precision reference regulators and the 400 Hz chopper/synchronous-rectifier system), the 15 Germanium auto-zero operational amplifiers (including substitution of OPA27 ICs for failed Germanium circuits), the timing/control relay section, and the removable patch panel. Dated February 2006 / January 2008 and attributed via contact email to [email protected].
- The TELEFUNKEN RA 742 Analog Computer
A single-page illustrated article from the Analog Museum describing the TELEFUNKEN RA 742 transistorized tabletop analog computer, covering its three-drawer architecture (power supply, function generators, and patch/control panel), and key specifications: 25 chopper-stabilized op-amps with 10^8 open-loop gain, four parabola multipliers, two diode function generators, 20 coefficient potentiometers, removable patch panel, and a total weight of 105 kg. The author also documents the experience of diagnosing and repairing the precision dual-rail +/-10 V power supply, and two sample calculations performed after restoration.
- The TELEFUNKEN RAT 700 Analog Computer
A descriptive overview article about the TELEFUNKEN RAT 700 desktop analog computer, introduced in 1961, featuring 19 operational amplifiers (15 chopper-stabilized), two variable diode function generators with 21-segment piecewise-linear approximation, four multipliers, and twenty 10-turn coefficient potentiometers. The article details the machine's four-drawer construction, patch panel wiring scheme, control panel functions (continuous, repetitive, and single-run modes), and internal circuit card design. Written by an analog computer enthusiast and collector at analogmuseum.org, with photographs and a historical reference to a 1965 magazine feature on a car suspension simulation using the RAT 700.
- The Very First TELEFUNKEN Analog Computer
A photo-essay and technical description of the RA 1, the first analog computer built by TELEFUNKEN, developed around 1955-1956 by Dr. Kettel, Dr. Schmidt, Dr. Kley and others. The machine is a three-rack, electron-tube system with a +/-100 V machine unit, featuring diode function generators, parabola multipliers (using EAA91 tubes), coefficient potentiometers, summers/integrators, dual oscilloscopes, and a precision system timer. The article details the operating principles of the parabola multiplier (exploiting the identity xy = ((x+y)^2 - (x-y)^2)/4) and the integrator state machine, and notes the absence of a central patch panel in favor of per-drawer front-panel interconnects.
- Difference Equations to Differential Equations — Section 1.1: Calculus: Areas And Tangents
Section 1.1 of Dan Sloughter's open calculus textbook 'Difference Equations to Differential Equations', introducing the two fundamental problems of calculus — computing areas and finding tangent lines — through the method of sequences and limits. The section uses inscribed regular polygons to approximate the area of a unit circle (arriving at pi) and secant-line slopes to approximate the tangent to the parabola y = x² at (1, 1), demonstrating that both problems reduce to evaluating limits of sequences. Eight problem sets reinforce the concepts with additional curves, polygon side counts, and numerical experiments.
- Difference Equations to Differential Equations — Section 1.2: Sequences
Section 1.2 of Dan Sloughter's open calculus text introduces sequences and their limits, developing the formal epsilon-N definition of convergence with worked examples. The section covers limit laws (scalar multiples, sums, products, quotients, and rational powers), criteria for divergence to infinity, and the Monotone Sequence Theorem with illustrative problems. Eighteen pages of theory and exercises make this a self-contained treatment of sequence convergence for a first calculus course.
- The Sum of a Sequence
Section 1.3 of Dan Sloughter's open calculus textbook 'Difference Equations to Differential Equations' introduces the concept of infinite series as limits of partial sums. The section develops the theory of geometric series, derives the closed-form sum formula for |r| < 1, and demonstrates applications including probability problems (coin tossing, animal reproduction), the economic multiplier effect, and the divergence of the harmonic series.
- Difference Equations to Differential Equations — Section 1.4: Difference Equations
Section 1.4 of Dan Sloughter's open calculus textbook introduces first-order difference equations, covering both the pure geometric form xn+1 = αxn and the general first-order linear form xn+1 = αxn + β. Applications include population growth, radioactive decay half-life calculation, and Newton's law of cooling, with explicit closed-form solutions derived and graphically illustrated. The section closes with sixteen exercises ranging from computing sequence terms to modeling the Fibonacci sequence and two-dimensional heat distribution.
- Difference Equations to Differential Equations — Section 1.5: Nonlinear Difference Equations
Section 1.5 of Dan Sloughter's open calculus textbook introduces nonlinear difference equations through the discrete logistic (inhibited growth) model, contrasting it with the linear uninhibited growth model. The section analyzes convergence behavior as the growth-rate parameter varies: convergence to the carrying capacity M for 0 < alpha <= 2, period-2 and period-4 limiting cycles for larger alpha values, and chaotic behavior near alpha = 2.95. Eight exercises reinforce the concepts using population-ecology scenarios and discrete dynamical systems.
- Functions And Their Graphs
Section 2.1 of the open textbook 'Difference Equations to Differential Equations' by Dan Sloughter, covering the foundational concept of functions and their graphical representations. The section defines functions, domain, range, function notation, composition, and major function classes (polynomials, rational, algebraic, transcendental), with worked examples drawn from physical scenarios. Practical guidance on computer-aided graphing, windowing, and point density is also included.
- Difference Equations to Differential Equations — Section 2.2: Trigonometric Functions
Section 2.2 of Dan Sloughter's open calculus text introduces trigonometric functions from right-triangle and unit-circle definitions, then develops amplitude, period, and phase-angle properties of sine and cosine. The section connects periodic functions to natural phenomena such as pendulum motion and sound waves, and closes with a brief introduction to Fourier series as sums of sine and cosine terms.
- Limits And The Notion Of Continuity
Section 2.3 of Dan Sloughter's open calculus text 'Difference Equations to Differential Equations,' covering the formal definition of limits for real-valued functions, one-sided limits, limits at infinity, and the notion of continuity. The section introduces the Heaviside function and piecewise examples to illustrate discontinuities, derives limit laws for polynomials and rational functions, and treats vertical and horizontal asymptotes via limit notation. Eighteen pages of exposition and problems are included.
- Difference Equations to Differential Equations — Section 2.4: Continuous Functions
Section 2.4 of Dan Sloughter's open calculus text covers the definition and properties of continuous functions, including continuity at a point, one-sided continuity, and continuity on open and closed intervals. The section proves continuity of polynomials, rational functions, algebraic functions, and trigonometric functions, and establishes that compositions of continuous functions are continuous. Worked examples and problem sets illustrate removable discontinuities and piecewise-defined functions.
- Some Consequences Of Continuity
Section 2.5 of the open textbook 'Difference Equations to Differential Equations' by Dan Sloughter, covering two fundamental consequences of continuity: the Intermediate Value Theorem and the Extreme Value Theorem. The section presents the bisection algorithm as a practical method for approximating roots of continuous functions on closed intervals, with worked numerical examples including root-finding for x^5 + x = 1 and optimization of a rectangular fencing problem. Practice problems reinforce both theorems and their computational applications.
- Difference Equations to Differential Equations: Section 3.1 Best Affine Approximations
Section 3.1 of Dan Sloughter's open calculus textbook introduces the concept of best affine approximations to functions, rigorously defining the tangent line as the unique affine function T whose approximation error R(h) is o(h) — that is, goes to zero faster than h itself. The section develops the formal definitions of o(h) and O(h) (little-o and big-O notation), works through several concrete examples including f(x) = sqrt(x) and f(x) = x^2, and culminates in the formal definition of the derivative as the slope of the best affine approximation.
- Best Affine Approximations, Derivatives, and Rates of Change
Section 3.2 of Dan Sloughter's open calculus text 'Difference Equations to Differential Equations' develops the concept of the derivative as the slope of the best affine (linear) approximation to a function at a point, establishing the formal limit definition. The section covers differentiability, the relationship between differentiability and continuity, Leibniz notation, and the interpretation of the derivative as an instantaneous rate of change, illustrated with worked examples including polynomial, radical, and absolute-value functions as well as a projectile-motion problem. A problem set of 20 exercises extends the material to finding derivatives, best affine approximations, tangent lines, and applied rate-of-change problems.
- Differentiation of Polynomials and Rational Functions
Section 3.3 from the open textbook 'Difference Equations to Differential Equations' by Dan Sloughter covers differentiation rules for polynomials and rational functions. The section derives and presents the power rule (d/dx x^n = nx^(n-1)) for positive and negative integer exponents, the constant multiple rule, the sum/difference rule, the quotient rule, and the product rule, with worked examples and practice problems.
- Differentiation of Compositions of Functions (Section 3.4)
Section 3.4 of Dan Sloughter's open calculus text 'Difference Equations to Differential Equations,' covering the chain rule for differentiating composite functions with formal proof and worked examples. The section extends power rule differentiation to rational exponents and introduces implicit differentiation, with applications to related rates problems. An 18-problem exercise set reinforces chain rule computation, implicit differentiation, and applied rate-of-change scenarios.
- Differentiation of Trigonometric Functions
Section 3.5 of 'Difference Equations to Differential Equations' by Dan Sloughter, deriving the derivatives of all six trigonometric functions from first principles using limit arguments. The section establishes the fundamental limits sin(h)/h → 1 and (cos h − 1)/h → 0 via geometric squeeze-theorem reasoning, then derives the derivative rules for sin, cos, tan, cot, sec, and csc. Worked examples apply the chain rule and product rule to composite trig expressions, with a problem set and a discussion of symbolic versus numerical differentiation.
- Difference Equations to Differential Equations — Section 3.6: Newton's Method
Section 3.6 of Dan Sloughter's open calculus textbook presents Newton's method as an iterative root-finding algorithm for equations of the form f(x) = 0. The section derives the recurrence relation x_{n+1} = x_n - f(x_n)/f'(x_n) from best affine (tangent-line) approximations and contrasts the method's speed with the bisection algorithm. Convergence conditions, failure cases (divergence, zero derivative), and worked examples including cos(x) = x and square-root approximation are covered, with problem sets extending to cube and seventh roots.
- Rolle's Theorem and the Mean Value Theorem (Section 3.7)
Section 3.7 of an open-source calculus text by Dan Sloughter, covering Rolle's Theorem and the Mean Value Theorem with full proofs. The section establishes that a differentiable function on an interval must attain its average rate of change as an instantaneous rate of change at some interior point, then applies this result to determine intervals of increase and decrease and to prove that two antiderivatives of the same function differ by a constant. Worked examples, geometric interpretations, and a problem set of 16 exercises are included.
- Difference Equations to Differential Equations — Section 3.8: Finding Maximum and Minimum Values
Section 3.8 of Dan Sloughter's open calculus textbook covers techniques for finding maximum and minimum values of continuous functions on both closed and open intervals. The section introduces critical points, singular points, the first derivative test, and the second derivative test for local extrema, illustrated with worked examples including trigonometric optimization, maximum likelihood estimation, and a cylindrical can surface-area minimization problem. A problem set of 22 exercises reinforces these techniques.
- The Geometry of Graphs
Section 3.9 from Dan Sloughter's open calculus textbook 'Difference Equations to Differential Equations', covering the geometry of function graphs using first and second derivatives. The section explains concavity (concave up/down), inflection points, and a systematic method for sketching graphs by combining information from f, f', and f'' along with asymptote analysis. Worked examples include polynomial, rational, and transcendental functions with detailed sign analysis.
- Difference Equations to Differential Equations — Section 4.1: The Definite Integral
Section 4.1 of Dan Sloughter's open calculus textbook introduces the definite integral via the quadrature problem — finding the area of a plane region bounded above by a continuous function and below by an interval on the x-axis. The section develops the formal definition using upper and lower Darboux sums, establishes integrability of continuous and piecewise-continuous functions, introduces left-hand and right-hand Riemann sum approximations with worked numerical examples, and covers linearity, additivity, and geometric sign conventions for the definite integral. Practice problems span approximation, geometric interpretation, and proof exercises.
- Difference Equations to Differential Equations: Section 4.2 — Numerical Approximations of Definite Integrals
Section 4.2 of Dan Sloughter's open calculus text presents four numerical methods for approximating definite integrals: the left-hand and right-hand rules (error O(1/n)), the trapezoidal rule and midpoint rule (error O(1/n²)), and Simpson's rule (error O(1/n⁴)). The derivations use the Mean Value Theorem and Taylor-polynomial arguments to bound errors rigorously, and worked examples illustrate convergence rates with tabulated approximations for benchmark integrals.
- The Fundamental Theorem of Calculus
Section 4.3 from Dan Sloughter's open textbook 'Difference Equations to Differential Equations,' presenting both the Fundamental Theorem of Integral Calculus and the Fundamental Theorem of Differential Calculus with full proofs. The section demonstrates that integration and differentiation are inverse operations, shows how definite integrals may be evaluated using antiderivatives, and proves that every continuous function has an antiderivative constructible via a definite integral with variable upper limit. Worked examples and problem sets covering evaluation of definite integrals, derivatives of integral functions, and area computations are included.
- Difference Equations to Differential Equations — Section 4.4: Using the Fundamental Theorem
Section 4.4 of Dan Sloughter's open calculus textbook 'Difference Equations to Differential Equations' presents the use of the Fundamental Theorem of Integral Calculus to evaluate definite integrals by finding antiderivatives. The section introduces indefinite integrals (general antiderivatives), standard integration formulas for polynomial and trigonometric functions, linearity properties, and the technique of integration by substitution (reversing the chain rule). Worked examples cover polynomial, trigonometric, and composite-function integrands for both indefinite and definite integrals, followed by a comprehensive problem set.
- Difference Equations to Differential Equations: Section 4.5 More Techniques of Integration
Section 4.5 of Dan Sloughter's open calculus textbook 'Difference Equations to Differential Equations,' covering integration by parts derived from the product rule, along with trigonometric identity techniques for evaluating integrals involving powers of sine and cosine. The section presents the standard udv = uv - vdu formula, works through numerous examples including definite integrals, and concludes with a problem set and discussion of computer algebra systems as modern tools for symbolic integration.
- Difference Equations to Differential Equations — Section 4.6: Improper Integrals
Section 4.6 of Dan Sloughter's open calculus textbook 'Difference Equations to Differential Equations' covers the theory of improper integrals, extending the definite integral to unbounded intervals and functions with infinite discontinuities. The section develops formal definitions, convergence and divergence criteria, comparison propositions (including absolute convergence), and the Cauchy principal value, illustrated throughout with worked examples and accompanied by a problem set.
- Difference Equations to Differential Equations: Section 4.7 More on Area
Section 4.7 of Dan Sloughter's open calculus textbook extends the definite integral to computing areas of regions bounded by two curves, treating both x-axis and y-axis formulations. The section derives the area formula via Riemann sum limits and works through several examples involving polynomial, trigonometric, and radical functions. A fourteen-problem exercise set follows, culminating in a Simpson's rule application for estimating lake surface area.
- Distance, Position, and the Length of Curves
Section 4.8 from Dan Sloughter's open calculus textbook 'Difference Equations to Differential Equations,' covering three applications of definite integrals: computing distance traveled from a velocity function, recovering position from velocity and initial conditions via the Fundamental Theorem of Integral Calculus, and deriving the arc-length integral formula for plane curves. The section includes worked examples involving oscillating springs, numerical integration, and curves such as y = x^(3/2), y = x^2, and y = sin(x), along with a ten-problem exercise set.
- Difference Equations to Differential Equations — Section 6.1: The Exponential Function
This 12-page chapter section from Dan Sloughter's open calculus text defines the exponential function exp(x) via its power series and derives its key properties: self-differentiation, the addition law exp(a+b)=exp(a)exp(b), and the identification exp(x)=e^x for all real x including irrationals. Differentiation and integration techniques are developed through worked examples, and the section closes with an uninhibited-population-growth application modeled by the differential equation x'(t)=λx(t) with solution x(t)=x0·e^(λt).
- The Natural Logarithm Function (Section 6.2)
Section 6.2 of Dan Sloughter's open calculus textbook 'Difference Equations to Differential Equations,' covering the natural logarithm function as the inverse of the exponential function. The section derives properties of log(x) including algebraic identities, the derivative (d/dx log(x) = 1/x), integral formulas, the Taylor series expansion about x=1, and the power rule extended to irrational exponents. Worked examples include differentiation via the chain rule, integration by substitution (tan(x), sec(x)), integration by parts for log(x)dx, and graphical analysis of y = log(x).
- Difference Equations to Differential Equations: Section 6.3 — Models of Growth and Decay
Section 6.3 of Dan Sloughter's open calculus textbook covers mathematical models of growth and decay using differential equations. Topics include compound interest (continuous compounding limit), uninhibited exponential growth and decay (population growth, carbon-14 dating), and the logistic differential equation for inhibited growth with solved examples fitting US population data. The section includes 14 practice problems.
- Integration of Rational Functions (Section 6.4)
Section 6.4 of Dan Sloughter's open calculus text 'Difference Equations to Differential Equations' covers the integration of rational functions using partial fraction decomposition. The section treats distinct linear factors, repeated linear factors, and previews irreducible quadratic factors (deferred to Section 6.5 on the inverse tangent). Worked examples and a problem set are included.
- Difference Equations to Differential Equations — Section 6.5: Inverse Trigonometric Functions
Section 6.5 of Dan Sloughter's open calculus textbook 'Difference Equations to Differential Equations' covers the definitions, graphs, derivatives, and integrals of the inverse trigonometric functions — arctan, arcsin, and arcsec. The section addresses partial fraction decomposition with irreducible quadratic factors, completing the square, and trigonometric substitution techniques. A substantial problem set extends coverage to arccos, arccot, arccsc, Taylor series for arctan, and approximation of pi.
- Difference Equations to Differential Equations — Section 6.6: Trigonometric Substitutions
Section 6.6 of Dan Sloughter's open calculus textbook presents trigonometric substitution as a systematic method for evaluating integrals containing radicals of the form sqrt(a^2 - x^2), sqrt(a^2 + x^2), and sqrt(x^2 - a^2). The section covers sine, tangent, and secant substitutions with worked examples, geometric interpretations via right-triangle diagrams, and a set of practice problems including both indefinite and definite integrals.
- Difference Equations to Differential Equations — Section 6.7: Hyperbolic Functions
Section 6.7 of Dan Sloughter's open calculus textbook introduces the six hyperbolic functions (sinh, cosh, tanh, coth, sech, csch), derives their derivatives and integrals from exponential definitions, and develops inverse hyperbolic functions with logarithmic closed forms. The section demonstrates how hyperbolic substitutions simplify integrals such as those involving sqrt(1+x^2) and sqrt(x^2-1), providing an alternative to trigonometric substitution methods. Practice problems covering differentiation, integration, and graphing are included.
- A Simple and Inexpensive Implementation of Time Division Multiplier for two Quadrant Operation
A four-page technical article published in IETE Technical Review (Vol. 12, No. 1, 1995) presenting a simple, low-cost two-quadrant time division multiplier (TDM) circuit built from standard CMOS and linear ICs. The circuit uses a sawtooth waveform generator, a comparator, and a low-pass filter to produce an output voltage proportional to the product of two input voltages. Experimental results tabulate accuracy within about 0.1% error for supply voltages up to ±5 V.
- LT1236 Precision Reference
Datasheet for the LT1236 precision buried-zener voltage reference IC, available in 5 V and 10 V versions. Key specifications include ultra-low drift of 5 ppm/°C maximum, 0.05% output accuracy, greater than 100 dB ripple rejection, and output current sourcing/sinking of up to 10 mA in series mode. The document covers electrical characteristics, typical performance curves, applications information (trimming, capacitive loading, Kelvin connections), and typical application circuits for A/D and D/A converters, precision regulators, strain-gauge conditioners, and temperature sensors.
- Simulation Accelerator
A one-page NASA spinoff article describing EAI Simulation Associates' Advanced Real-Time System (ARTS) simulation accelerator, developed under Goddard Space Flight Center SBIR contracts. The system employs an analog model of computation and a scheduling compiler that maps continuous-system source code directly onto data-flow hardware with fine-grain parallelism, achieving better-than-supercomputer performance. A Space Shuttle main engine benchmark — requiring 40 integrators, several hundred summers and multipliers, 38 dividers, and 32 arbitrary function generators — ran in real time with four processors, more than eight times faster than a supercomputer; five ARTS systems were sold commercially through Halifax Corporation.
- CSI Computer System/Remote Interface Unit Acceptance Test Results
NASA Technical Memorandum 104218 (March 1992) reporting acceptance test results for the Control/Structures Interaction (CSI) Computer System (CCS) and Remote Interface Unit (RIU) installed at the Space Structures Research Laboratory, Langley Research Center. The RIU provides 16 analog input channels through a 12-bit A/D converter and 8 output channels through 12-bit D/A converters, with analog anti-aliasing filters and a DSP board for digital filtering; the CCS uses spaceflight-qualified 1750A CPU and array processor hardware communicating over a MIL-STD 1553B bus. Test results cover hardware acceptance, software/control computation verification, open- and closed-loop tests, digital filtering, and standalone RIU operation.
- The Analog Computer
A five-page magazine article from Electronics and Technology Today (August 1988) that introduces analog computing to a general technical audience, covering the history from mechanical to electronic machines and a comparison of analog versus digital computing. The article details the three core computing elements (coefficient multiplier, summer, integrator) and demonstrates problem setup and patching using the classic mass-spring-damper car suspension model. The author also describes a custom analog computer designed and built at Aberdeen University, including its modular panel architecture, color-coded patch sockets, BBC Micro interface for hybrid operation, and precision power supply design.
- EAI Computer Users' Group Newsletter, Fourteenth Edition
The fourteenth edition (February 1986) of the EAI Computer Users' Group International Chapter newsletter covers the 1985 users' group meeting held in Genova/Santa Margherita, Italy, with 27 attendees from eight countries. Technical content includes EAI product status reports on the SIMSTAR non-homogeneous multiprocessor (including the Gould CONCEPT 32 digital arithmetic processor family integration, STARTRAP programming system, and ACSL-compatible real-time DAP simulation language), plus user-presented papers on analog and hybrid simulation of satellite attitude controllers, servomechanisms, gas utility systems, motor-vehicle drives, DFVLR research aircraft, and interface experiences with the EAI 2000. News from the North American Chapter and articles of organization are also included.
- VERO Analog-Computer AC 46093 — Application Electronics
German-language operator manual and application guide for the VERO AC 46093 analog computer, a compact briefcase-form educational machine developed by BICC-VERO in collaboration with Hochschule Bremen. Covers operating modes (IC/OP/POT), computing elements (6 integrators, 3 summers, 3 difference amplifiers, 2 multipliers, 12 coefficient potentiometers, 4 diodes), technical specifications, master-slave linking of multiple units, and an applied example of DC motor speed-control simulation.
- SIMSTAR — An Attached Multiprocessor for Dynamic System Engineering
StarLight Product Information Bulletin No. 04 (July 1983) describing the EAI SIMSTAR attached multiprocessor for dynamic system engineering. SIMSTAR combines a Parallel Simulation Processor (PSP), a Parallel Math Unit (PMU), and a Digital Arithmetic Processor (DAP) to achieve up to 200 million Normalized Operations Per Second (NOPS), enabling real-time or faster-than-real-time simulation of complex continuous and discrete systems. The system attaches to a host computer and is programmable via FORTRAN or the STARTRAN simulation language, with architecture supporting mixed analog, digital, and hybrid computing methodologies.
- SIMSTAR – An Attached Multiprocessor for Dynamic System Engineering
A technical paper presented at the 1983 Summer Computer Simulation Conference describing the EAI SIMSTAR attached multiprocessor system for dynamic system simulation. SIMSTAR combines high-speed parallel digital arithmetic processors (delivering up to 200 million Normalized Operations-Per-Second), programmable logic, function generation hardware, and a FORTRAN-based simulation language (STARTRAN) to provide cost-effective large-scale continuous simulation. The system attaches to a host computer and integrates parallel math units, digital-to-analog signal conversion, and vector processing to simulate differential equations at frequencies ranging from 30 Hz (structural dynamics) to over 100 kHz (electronic circuits).
- DO 910 Simulationssystem — Technisches Handbuch
Technisches Handbuch for the Dornier DO 910 hybrid simulation system, covering system overview, disassembly/reassembly, calibration of all analog computing element modules (summing amplifier, integrator, multiplier, variable function generator, dead-time element), IEC/IEEE-488 bus interface, ADC and MDAC calibration, and full schematic diagrams for all plug-in boards. The DO 910 uses a ±10 V machine unit with ±15 V/±12 V/+5 V supply rails and is controlled by a Commodore CBM 4032/8032 computer via an IEC/IEEE-488 bus.
- Der Analogrechner
Second edition (February 1982) of a comprehensive German-language programming and applications manual for the Leybold-Heraeus analog computer. Written by Dr. Martin Hund, the book provides 150 program examples drawn from mathematics, control engineering (Regelungstechnik), and physics, covering basic operational-amplifier circuits, multiplier configurations, diode function generators, ODE solvers, and physical simulations (kinematics, ballistics, oscillations, Schrodinger equation). Includes detailed instructions for amplitude and time scaling, calibration, recorder/oscilloscope recording, and use of the programmable switch accessory (576 07).
- EAI 2000 Analog Reference Handbook
Comprehensive reference handbook for the EAI 2000 analog/hybrid computer system, covering system overview, the program panel layout, all analog computing components (coefficient units, summers, integrators, multipliers, function generators, limiters), logic computing components, system and interface components, and the MACS (Master Analog Computer System) display and keyboard command set. The handbook serves as the primary operator reference for programming, patching, and operating the EAI 2000 in stand-alone analog, hybrid non-time-critical, and hybrid time-critical configurations. Published April 1980 as Pub. No. 00 800.2107-0 RC0.
- Systemanalyse und Reglerentwurf am Beispiel einer elektromagnetischen Aufhängung
A 74-page German Studienarbeit (student research thesis) from the Institut für Mess- und Regelungstechnik, Universität Karlsruhe, submitted in 1980 under Prof. Dr.-Ing. F. Mesch. The work performs a system analysis and PID controller design for an electromagnetic (magnetic) suspension — an inherently unstable, nonlinear plant — and demonstrates how the linearized closed-loop system is simulated on an analog computer. Topics include derivation and linearization of the equations of motion, measurement of the force-distance characteristic and optical sensor curve, root-locus controller synthesis, cascade current-loop design, normalization for the analog computer, and a revised laboratory experiment guide ('Analogrechner II').
- EAI 1000 Reference and Maintenance Manual
The Reference and Maintenance Manual for the EAI-1000 Micro Processor Controlled Analog/Hybrid Computer System covers the architecture, operating procedures, and maintenance of this education-oriented hybrid computing system. The EAI-1000 is built around a modular bus system supporting up to three CD analog modules, a display module, a microprocessor control card, and optional digital expansion; analog computing elements include integrators, summers, multipliers, comparators, potentiometers, and free-function generators. The manual details all computing components and their patch-panel connections, digital logic elements (gates, flip-flops, counters), control modes (IC/OP/REP), overload protection, circuit schematics, and parts listings for maintenance purposes.
- Analogue Computer (Part 1)
A multi-part constructional article from Practical Electronics magazine (September 1978, Vol. 14 No. 13) describing how to build a general-purpose analogue computer. Part 1 covers the mathematical operations achievable with op-amp circuits — summation, integration, and coefficient multiplication — and explains how these building blocks are interconnected to simulate physical systems. Practical circuit diagrams and example applications (velocity, distance, oscillatory motion) are included alongside theory.
- Practical Electronics, September 1978 — Analogue Computer Part 1: Mathematical Operations and Circuits
First installment of a multi-part constructional series on building an analogue computer, published in Practical Electronics (Vol. 14, No. 13, September 1978). Covers the fundamental theory and circuit building blocks: summing amplifiers, integrators using 741 op-amps, coefficient multipliers (potentiometers), and mode-control logic (Compute / Hold / Reset with Initial Conditions). An overload warning facility is also described. Construction details were deferred to Part 2 (October 1978 issue).
- Practical Electronics, October 1978 — Analogue Computer Part 2: Construction Details
Part 2 of a multi-part constructional series from Practical Electronics (October 1978) covering the build details of a ten-amplifier analogue computer. The article describes the main PCB layout for ten computing elements (summers and integrators using 741 op-amps), two AD533JD four-quadrant multiplier ICs, relay-based mode control (Compute/Hold/Reset), an overload warning circuit with comparators and LEDs, and a 148-socket colour-coded patch panel. A components list and stage-by-stage construction guidance are included, with wiring and testing deferred to the following issue.
- Practical Electronics, November 1978 — Analogue Computer Part 3: Wiring, Testing and Programming
Third and final construction installment of the Practical Electronics homebrew analogue computer series, covering mechanical assembly into the case, full wiring schedules for eight edge connectors, offset-null trimming and mode-control testing of all ten computing amplifiers, and programming techniques illustrated by worked examples including ramp/square-law function generation, initial conditions, and the spring-mass oscillator. The issue also contains the Moon Landing game article, which independently uses an analogue computer circuit to simulate rocket descent kinematics.
- Practical Electronics, December 1978 — Analogue Computer Part 4 (Conclusion)
The concluding instalment (Part 4) of a four-part constructional series on building and programming a home-constructed analogue computer, published in Practical Electronics, December 1978. The article by P. J. Kronis covers programming techniques including damping systems (impulse, step, sinusoidal and random forcing functions), Lissajous figures, flight simulation of a lunar lander with amplitude and time scaling, and a survey of special circuits such as diode limiters, dead-zone, absolute-value, and flip-flop circuits. The issue also contains a corrected patch-panel diagram (Fig. 3.2) that was misprinted in Part 3.
- Moon Landing Game
A five-page construction article from Practical Electronics (November 1978) describing a small analog computer game that simulates a lunar module descent. The circuit uses operational amplifiers to model the physics of the lander — computing velocity, altitude, and fuel consumption in real time — while the player controls the rocket motor to achieve a soft landing. The article covers the schematic, component list, PCB layout, panel wiring, and calibration procedure.
- Analogrechner Do 80 / Analog Computer Do 80
Bilingual German/English product brochure for the Dornier Do 80, a compact 10 V, 19-inch rackmount analog computer manufactured by Dornier System GmbH. The brochure covers the machine's control and indicator elements, computing element modules (integrators, summers, multipliers, variable function generators, logic modules, counters, and death-time delay generators), patching examples for common mathematical operations, and full technical specifications. Key specs include ±10 V reference, 220 V/50 Hz supply (~100 VA), summer bandwidth of 80 kHz, integrator capacitors of 1 µF/0.1 µF/0.01 µF, and TTL logic components.
- HSE-Analog-Computer: Eine Neuentwicklung für die biomedizinische Forschung
A four-page German sales brochure (dated 1.1.1977) for the HSE Analog Computer, a medium-scale analog computer designed specifically for biomedical research applications such as pharmacokinetics and cardiovascular physiology. The machine provides 32 integrators, 32 summers, 16 multipliers, 8 function generators, and 32 coefficient potentiometers at approximately 1% computational accuracy, targeting a price point below large mainframe computers. The brochure includes a detailed component list, pricing in Deutsche Mark (DM 54,100 fully equipped), and a worked pharmacokinetics programming example demonstrating substance transport among stomach, blood, and urine compartments.
- Ein elektronischer Koordinatenwandler ohne Diodennetzwerke und seine Anwendung bei der Messwertverarbeitung mechanischer Groessen
A 1977 doctoral dissertation submitted to the Technische Universitat Wien by Dipl.Ing. Fritz Vogel. The work describes a novel electronic coordinate converter that converts Cartesian coordinates to polar coordinates without diode networks, using an arctangent approximation based on the hyperbolic tangent function. The dissertation covers analog and digital implementation methods, circuit design, four-quadrant operation, computational accuracy analysis, and application examples including acceleration measurement and biaxial stress analysis.
- Analogrechner Dornier 80 Bedienungs-Handbuch
Operating manual for the Dornier DO 80 analog computer, published January 1976 by Dornier System GmbH, Friedrichshafen. Covers the front-panel controls and rear-panel connections of the DO 80, including the 16 plug-in computing-element positions, potentiometer and timing controls, operating modes (IC, single-run, repetitive), remote-control interface, and voltmeter subsystem. Intended both as a beginner operating guide and a reference for special circuit configurations.
- Zeichnungssatz DO80 Analogrechner
A nine-page drawing set (Zeichnungssatz) for the Dornier DO80 Analogrechner, published by Dornier-System GmbH and Dornier AG, Friedrichshafen. The set comprises a master drawing index, sub-assembly parts lists, a photographic assembly overview, two-page assembly hierarchy block diagrams (covering housing, power supplies, control unit, computing elements, logic elements, and peripherals), three overview schematics (external connection leads, manual switches with relays, and the T/10 timer divider circuit), and a special manufacturing tools list. Documents are dated May 1973 through July 1975.
- Totzeitglieder für den DO 80 Analogrechner — Beschaffungs- und Entwicklungsunterlagen
A compilation of internal correspondence, technical descriptions, circuit diagrams, and supplementary material relating to the development and procurement of dead-time (Totzeitglied) plug-in modules for the Dornier DO 80 analog computer, dated 1973–1975. The core preliminary description documents an 8-bit A/D and D/A converter architecture with a 100-word shift register, providing adjustable dead-time delays from 1 ms to 10 s in three ranges, selectable via a continuously variable input; the module occupies one single-width DO 80 slot. Supporting material includes Siemens and Dornier procurement letters, internal distribution memos, Helipot resistor-network and AEG-Telefunken LZG 100 delay-unit data sheets, and an English-language Monte Carlo simulation article from Electronic Design (February 1973).
- Analogrechner AR 12
Technical description and operator manual for the Frey Analogrechner AR 12, a compact 19-inch desktop analog computer with 12 computing amplifiers (6 integrators, 6 summing amplifiers), 5 computing voltages, and 5 computing potentiometers housed on Eurocard plug-in boards. Covers operating principles, front-panel controls and jack-field layout, calibration and offset-adjustment procedures, individual plug-in card specifications (RB 23 amplifier, RB 24 integrator, RB 37 oscillator, RB 89 HF filter, RB 91/SN power supplies), and a 1973 price list with three model variants ranging from DM 2,580 to DM 5,420.
- Methodik der rechnergestützten Simulation — Fachgespräche vom 10.–11. Mai 1973
Proceedings of a May 1973 German-language workshop on computer simulation methodology, jointly organized by the Kernforschungszentrum Karlsruhe and the University of Stuttgart (report KFK 1845, 425 pages, 33 contributed papers). Topics span real-time simulation of time-continuous systems, hybrid analog-digital simulation architecture (including HYBRIDMASTER mode control and SCALE/CSMP/MUNICH/DYNAMO programming systems), validation of discrete and continuous simulation models, Monte Carlo methods, and diverse application domains including road traffic, reactor technology, telecommunications networks, satellite attitude control, and human-vehicle systems.
- EAI 180 Computer Operator's Reference and Maintenance Manual
The Operator's Reference and Maintenance Manual for the EAI 180 Analog-Hybrid Computer covers initial set-up, operating procedures (readout and meter control, display and mode control, digital control), and detailed descriptions of all computing components including linear (summers, integrators), non-linear (function generators, comparators, multipliers), and digital logic elements. The manual also includes maintenance procedures for the main frame and each panel type, three appendices on unit scaling, transfer-function simulation, and representation of constraints and nonlinearities, plus a full set of circuit diagrams for all major sub-assemblies. The EAI 180 is a compact, solid-state general-purpose analog-hybrid computer designed for office or classroom use, rated for 240V/50Hz or 110V/60Hz operation.
- Die Differentialgleichung und ihre Lösung mit den Operationsverstärkern; Grundlagen einfacher Regeleinrichtungen
A January 1972 PEK Electronic application note (document numbers L 1112 and L 2310) covering two related topics in 18 pages. The first part (L 1112) explains how to solve ordinary differential equations using op-amp integrator circuits, covering single and double integration, differentiation, time transformation, and a worked RL-circuit simulation example. The second part (L 2310) introduces the fundamentals of simple electronic controllers — P, I, PI, and D types — realized with op-amps, including step-response waveforms and transfer functions.
- Analogrechner für den Lehrer (Analog Computer for the Teacher)
Teacher's supplement for PEK Electronic analog computer laboratory exercises, dated January 1972. Each sheet (A 1350–A 1360) corresponds to a student exercise and provides instructors with expected measurement results, circuit analysis notes, and pedagogical guidance for topics including sawtooth waveform generation, step-function generation, factor formation, summation, integration, differential equations, parabola multipliers, servo-multipliers, and PID controller construction.
- Analogrechner Versuche 1: Versuchsbeschreibungen für Platte 38500
A set of three guided laboratory experiments for the PEK Electronic 38500-series analog computer system, published January 1972. The experiments cover: (1) measuring integrator output voltage as a function of time with various time constants using Board 38503; (2) generating and observing step functions (Z-Sprung) using the integrator and oscilloscope with Board 38501; and (3) measuring the voltage transfer characteristics of the three potentiometer types (P1–P3, P4–P9, P10–P15) on Board 38501 to understand coefficient scaling. Equipment referenced includes Boards 36013, 38501, 38503, 38506, 38508, and 38509.
- Versuchsbeschreibungen: Summierung und Integration mit dem Analogrechner (Versuche 2)
A January 1972 set of structured laboratory exercise guides (Versuchsbeschreibungen) for the PEK analog computer system, covering three experiments: summation with the analog computer (Experiment II), integration (Experiments II/III), and solving an integral equation. Each exercise provides a circuit description, required modules list (types 38013, 38501–38509), step-by-step measurement procedure, and data tables for recording results. Intended for students learning to configure the PEK modular analog computer's program panel for basic mathematical operations.
- Versuchsbeschreibung: Anwendung des Servo-Multiplizierers / Aufbau und Wirkungsweise eines PID-Reglers
A two-part German-language application note (January 1972, document numbers A 1357 and A 1360) from PEK Electronic describing laboratory experiments for the PEK Analogrechner Typ 38500 series. Part 1 covers the theory and hands-on exercises for the servo-multiplier (Type 38507), including multiplication, squaring, and division circuits with step-by-step measurement tables. Part 2 addresses the construction and operation of a PID controller implemented on the analog computer, including damped and growing oscillation experiments recorded via X-Y plotter.
- Der Analogrechner als Lehr- und Übungsgerät in der Regelungstechnik
A 20-page German-language lab manual and demonstration proposal (PEK document A 1362, January 1972) based on a lecture by Dipl.-Ing. G. Jarbe, showing how the analog computer can serve as a teaching and practice tool in control engineering. The document presents the simulation of a second-order mechanical/electrical oscillatory system using integrators and RC networks, then demonstrates closed-loop control behavior with P- and PD-controllers applied to the same plant, illustrating the effects of varying gain and damping. Numerous oscilloscope-trace diagrams show step responses for different controller parameter settings.
- Totzeitglied
Engineering report produced after a ten-week internship at Dornier Friedrichshafen (October 1971), describing a dead-time element add-on unit for the DO 80 analog computer. The unit implements variable delay (1 ms to 10 s) via an analog-to-digital conversion chain: input op-amp (AD 503) compresses ±10 V to 0–10 V, an ADC 540-8 digitises to 8-bit words, a 100-position Signetics 2510k shift register provides the programmable delay, and a DAC 371-8 with output op-amp reconstructs the ±10 V analog signal. A VCO (8038) clocks the chain at a rate controlled by a panel voltage, and control logic interfaces the unit to the DO 80 bus (Compute/Halt/Initial Condition modes). Detailed circuit analysis, component selection, calibration procedures, oscillograms, and a full schematic are included.
- Handbook of Analog Computation
A comprehensive second-edition handbook covering all major aspects of electronic analog computation, prepared by EAI's Education and Training Department. The 401-page volume addresses mathematical modeling, general-purpose analog computer architecture, programming and problem-checking procedures, linear and non-linear systems analysis, function generation, transfer function and transport-delay simulation, repetitive operation, analog memory, partial differential equations, solution accuracy, efficient programming practices, and laboratory planning. Appendices provide Laplace transform tables, transfer function circuits, diode and relay circuits, and a selected applications bibliography.
- Golf Game Computing System (US Patent 3,598,976)
US Patent 3,598,976, patented August 10, 1971, describing an analog computer-based golf game simulation system invented by Jack A. Russell and Bradford J. Baldwin. The system uses sensors to detect the trajectory of an actually-struck golf ball and feeds the measurements into an analog computing circuit that calculates and displays where the ball would land on a real golf course. The patent includes 17 sheets of detailed circuit schematics and system diagrams covering the sensor array, analog computing elements, and display apparatus.
- Aufbau und Inhaltsbeschreibung des Analogrechners Typ 38500
An 8-page German-language technical description (December 1971) of the construction and board-by-board content of the PEK Electronic Analog Computer Type 38500. Covers the ten plug-in computing boards including potentiometers (38500), two summing amplifier boards (38501/38504), integrators (38503), two multiplier boards (38505/38507), the programming patch field (38506), measured-value display (38508), operating and control board (38509), and the dual power supply unit (36013/A3). The system operates at ±15 V; boards use DIN A3 Eurocard format and fit into a fold-out demonstration housing.
- Ausbildungsausstattung Analogrechner Wirkungsweise Typ 35 957: Geräte und Funktionsbeschreibung, Bedienungsanleitung
Operating instructions and device/functional description for the PEK Electronic Type 35 957 analog computer training kit (1st edition, 1971), prepared by Dr.-Ing. Paul E. Klein. Covers the educational significance of analog computers, component symbols (potentiometer, summing amplifier, integrator, multiplier, divider, comparator, function generator), a structured table of contents for exercises from basic voltage generation through PID controller experiments, and a full parts list of PEK teaching boards and accessories included in the kit.
- Beschreibung des Digitalzusatzes DEX 802
Program information document (July 1971) describing the DEX 802 digital supplement for the Telefunken hybrid analog-digital computing system. Covers the structure and function of the double-width plug-in unit with 24-slot magazine for interchangeable digital logic elements (NAND, NOR, flipflops, counters), technical data (logic levels 0V/+5V-12V, fixed clocks 10 us to 2 s), operating instructions for the DPF digital programming field and DBG control device, and an alphabetical bus and element reference.
- Kurzgefasste Bedienungsanleitung fur den Telefunken Analogrechner RA 770
An abbreviated operating guide (48 pages, April 1971) for the Telefunken RA 770 analog computer system, covering startup procedures, insertion of pre-programmed Analog Program Files (APP), operation of the central control unit, computing element control, potentiometer settings including time base and 4-quadrant configuration, and an overview of computing elements such as integrators, summers, multipliers, resolvers, and variable function generators. The RA 770 supports hybrid operation with a DEX 802 digital voltmeter readout and two-computer parallel operation (main computer HR and sub-computer NR). Based on study paper No. 551 by R. Abenhold and intended as a condensed companion to the full Telefunken operating manual.
- EAI — Report Nr. 017, April–Mai 1970
Issue 17 (April–May 1970) of EAI Electronic Associates GmbH's German-language customer newsletter, covering new EAI-640 digital computer configurations (640/100, 640/200, 640/300) and peripherals, hybrid expansions for the TR-48 analog computer, installation reports for the EAI-680 at Technische Hochschule Wien and EAI-590 at DFVLR Braunschweig, and the EAI-690 hybrid system. Includes a technical article on amplitude and phase measurement using the analog computer (by Dipl.-Ing. F. Vogt), plus product announcements for the EAI 430/200 Data Plotter, Brush Mark 220/260 strip-chart recorders, DCFG (Digitally Controlled Function Generator), and the DART data acquisition and recording terminal.
- Analog/Hybrid — What It Was, What It Is, What It May Be
A survey article by Arthur I. Rubin of Electronic Associates, Inc. (EAI), presented at the Fall Joint Computer Conference (FJCC) 1970. It traces the evolution of analog and hybrid computers from WWII 'zeroth generation' machines (BEAC, EASE, GEDA, REAC) through successive generations defined by patch panels, improved component accuracy, and the introduction of digital elements, to the hybrid systems of 1970, and speculates on their future. Key manufacturers (EAI, Beckman/Berkeley, Reeves, Philbrick, GPS) and landmark machines are discussed alongside accuracy milestones, application domains, and the historical tension between analog flexibility and digital precision.
- Designer's Manual for Circuit Design by Analog/Digital Techniques
A designer's manual from Tulane University's Department of Electrical Engineering covering hybrid analog/digital computer techniques for electronic circuit design, dated July 1970. Topics include hardware requirements for hybrid systems, recommended analytical methods (indirect analog simulation, nonlinear semiconductor device modeling, function generation), and representative design examples using the NASAP (Network Analysis System Applications Program) software. The manual demonstrates circuit design workflows using the Tulane hybrid computer facility comprising EAI analog computers and a Univac digital computer.
- Beziehung zwischen Produktion und wirtschaftlichen Prozessen — dargestellt an einem Analogie-Rechenmodell für den Analogrechner MEDA 1
A German-language research paper from the Freiberger Forschungshefte (Freiberg Research Papers) series presenting a dynamic analog-computer model of the relationship between production output, procurement, and inventory in an economic system. The paper formulates the model as a set of coupled ordinary differential equations, derives stability conditions, and provides the complete block diagram and patch diagram for implementing the simulation on the East German MEDA 1 small analog computer. Results demonstrate convergent and oscillatory regimes depending on the model's lag-time parameters.
- EAI 380 Analog/Hybrid Computing System
Marketing brochure and specification sheet (Bulletin No. 853094-2 / 853089-1, dated April 15, 1969) for the EAI 380 10-volt desk-top analog/hybrid computer. The document describes the system as EAI's lowest-cost hybrid-capable machine, expandable from 10 to 54 amplifiers in a single mainframe, with features including electronic mode control, quarter-square multipliers, variable diode function generators, high-speed comparators, a self-contained digital voltmeter, and an integrated-circuit plug-in logic system. Full component specifications are provided covering operational amplifiers, integrators, summers, inverters, multipliers, track/store networks, comparators, function relays, sine/cosine generators, and digital logic cards.
- EAI 680 Maintenance Pocket Guide
A compact pocket guide prepared by the EAI Technical Training Department to assist technicians maintaining the EAI 680 analog/hybrid computer, published October 1969. The guide covers operating equipment (patch cords, pins, connectors), a full inventory of major computing trays (analog, control, and logic types with old- and new-series part numbers), patch panel overlays, special tools and accessories, expendable supplies for peripheral units (8850 plotter, 8875 recorder, 8880 display, 8881 monitor oscilloscope), connector repair kits, fuses, lamps, and a semiconductor replacement guide listing direct replacements, substitutes, and special-category diodes and transistors. Console adjustment diagrams, bus layouts, plug-in component and integrated-circuit pin layouts, and chassis connector layouts are included as fold-out illustrations.
- EAI-Mitteilungsblatt Nr. 015 — EAI Electronic Associates GmbH
The EAI Mitteilungsblatt (newsletter) Nr. 015, covering August 1968 through April 1969, is a multi-article German-language customer bulletin from EAI Electronic Associates GmbH in Aachen. It introduces the new EAI-7800 analog/hybrid computer (294 amplifiers, 100 V reference, 42 integrators, 36 multipliers, configurable for hybrid operation with the EAI-640 digital computer), describes the EAI-590 hybrid system (comprising the EAI-580 analog computer, EAI-640 digital computer, and EAI-693 interface), and reports on the EAI-8900 installation at the UK Central Electricity Generating Board. Additional articles cover EAI's role in NASA Apollo simulations, the PACE II analytical data-processing system for gas chromatography, a driving simulator at TU Berlin using TR-20 analog computers, the 1969 European training course calendar, and a new digital drafting template.
- EAI Report Nr. 016 — Mitteilungsblatt der Electronic Associates GmbH
EAI Report Nr. 016 is a German-language company newsletter (May–June 1969) from Electronic Associates GmbH, Aachen. It covers Clevite/Brush strip chart recorders (including the Mark 280 6-channel portable and the Datapoint multipoint recorder), introduces the EAI 430 Dataplotter (an XY plotter with RAPID polynomial interpolation), presents a technical article on autocorrelation analysis of stochastic time functions using hybrid computers (including the EAI-380), and includes a programming exercise on the pursuit problem, a Hannover-Messe 1969 trade-fair report, an Apollo 9 tribute, the EAI 380 system description, a trade-in program announcement, and MC laboratory connector accessories.
- Introduction to Simulator (Part 1)
The first part of Hitachi's Technical Information Series No. 9 introduces simulator applications for civil and structural engineering problems using analog and hybrid computers. It covers flood prediction methods including the storage function, unit graph, and outflow function approaches, showing how the governing differential equations are implemented on analog hardware. A second major section describes earthquake response simulation using the SERAC (Strong Earthquake Response Analysis Computer) analog computer, treating linear and non-linear single- and multi-mass-point vibration models of high-rise buildings; the SERAC system comprises integrators, special integrators, adders, inverters, potentiometers, function generators, and voltage comparators.
- Introduction to Simulator (Part 2)
The second installment of Hitachi's Technical Information Series No. 10 surveys four analog-computer simulation applications: pipe network flow analysis (using electrical analogs of the Hazen-Williams and Williams-Hazen equations), voice synthesizers (spectrum-analysis and configuration-analog methods), nerve-cell and nervous-system models, and cardiovascular/respiratory system simulators. Each topic is supported by circuit diagrams and block diagrams illustrating how the Hitachi analog-hybrid computer is programmed to represent the corresponding physical or biological phenomena. The document serves as an introductory survey of biomedical and engineering simulation capabilities available on Hitachi analog-hybrid equipment.
- Partial Differential Equations for Heat Conduction Analysis of Frozen Layer Shifting
Technical Information Series No. 11 from Hitachi demonstrates how the heat-conduction partial differential equation governing the shifting of a frozen soil layer is converted to a set of finite-difference equations and solved on a Hitachi analog-hybrid computer. The document derives boundary conditions for a one-dimensional frozen/unfrozen soil column, scales the equations to machine variables, and presents temperature-transition curves (time and depth as parameters) obtained from the simulation. A full block diagram for the HITAC 505 High-Precision Analog Computer implementation is included, showing 7 integrators, 19 summing amplifiers, 12 sign-changers, 7 potentiometers, 2 dead-zone units, and 15 diodes.
- Learn About Analog Computers: Reprints from Hydrocarbon Processing
A collection of reprinted articles from Hydrocarbon Processing (Gulf Publishing, 1969) by Gadmon and Smith of the University of Maryland, covering analog computer theory and practice for chemical and petroleum engineers. Topics span from introductory component identification (potentiometers, high-gain amplifiers, integrators) through magnitude and time scaling, simulation of dynamic systems, nonlinear function generation, algebraic solutions, and hybrid computation. The series addresses practical programming and application to process engineering problems such as distillation, reactor optimization, and multi-tank dynamics.
- DIN 40700 Blatt 18: Schaltzeichen — Analogrechentechnik
DIN 40700 Sheet 18 (October 1969) is the German national standard defining graphical circuit symbols for analog computing technology. It catalogs 40 standardized symbols for linear computing elements (summing amplifiers, integrators, complementary integrators, track-and-hold units), nonlinear elements (multipliers, dividers, function generators, limiters, comparators), and hybrid (analog-digital) elements. The standard was prepared by the Electronics Standards Committee of the German Standards Institute (DNA) in alignment with IEC recommendations.
- Dynamische Simulatoren in der Reaktorentwicklung. Ein Vergleich
A 1969 external technical report (No. 8/69-1) from the Kernforschungszentrum Karlsruhe comparing analog, digital, and hybrid dynamic simulators for nuclear reactor development applications. The authors evaluate simulator types against criteria of computational accuracy, speed, cost, and ease of use, with emphasis on stiff differential equation systems arising in reactor kinetics and thermal-hydraulics. Benchmark test cases compare specific systems including EAI HYDAC, Telefunken RA 800, IBM 360 with CSMP, and a large hybrid system (~500 op-amps), concluding that hybrid computers offer the best performance for demanding reactor-dynamics problems while digital simulation is preferred for precision work.
- Perspektivische Darstellung von Rechenergebnissen mit Hilfe eines Analogrechners
A short AEG-Telefunken application note (7 pages, document ASD 051 0469) describing how an analog computer can generate perspective (three-dimensional) representations of computed results on an oscilloscope by adding weighted projections of a third variable z to the X and Y deflection channels. The note presents five circuit variants using multipliers and potentiometers to set a fixed or continuously rotating viewing angle, and illustrates the technique with a damped oscillatory differential-equation system whose phase-plane trajectory is displayed as a rotating 3D spiral at multiple viewing angles.
- Simulation von Schwingungssystemen mit Analogrechnern
A 22-page technical paper by Dr. H. Kramer (Staatliche Ingenieurschule Konstanz), contributed to a VDI-Bildungswerk course (Dusseldorf 1969) on solving control and vibration problems with industrial and self-built analog computers. Part I covers qualitative and quantitative analog simulation of linear spring-damper-mass oscillators, including time and amplitude normalization, maximum-value estimation under initial-condition, step, and periodic forcing, and generation of undamped oscillations. Part II treats nonlinear and continuous systems: the mathematical pendulum (small and large deflections), oscillators with nonlinear damping and bistable restoring forces, two-mass systems, and modal simulation of a jumping beam.
- EAI 580 Analog/Hybrid Computing System Maintenance Series: Console Components
This is the Console Components volume of the EAI 580 Analog/Hybrid Computing System Maintenance Series (Publication No. 00 800.2056-0, May 1968), covering eight chapters: system introduction with installation data, general maintenance procedures, computer mode and time-scale control, readout selector system, servo and handset attenuators (up to 70 motor-driven units), overload indicators, the 0.10.0354 power supply (plus/minus 10 V reference, plus/minus 15 V, +30 V regulated outputs), and AC/DC power distribution including the motorized patch-panel drive. Each chapter includes theory of operation, troubleshooting guidance, replaceable-parts lists, and wiring diagrams; Appendix 2 reproduces the 21-sheet console wiring drawing D00 093 0062 OW.
- Computer Mode and Time Scale Control System (EAI 580 Console Manual, Chapter 3)
Chapter 3 of the EAI 580 console manual describes the computer mode and time scale control system, covering the six operating and setup modes (OPERATE, HOLD, INITIAL CONDITION, STATIC TEST, SET POT, PROGRAM PANEL), the 0.12.1607 Control Tray, and the analog timer circuits with four integrator time scales from 0.2 ms to 1.0 sec. The chapter includes theory of operation for the mode selection flip-flop logic, the rep-op timer card, and peripheral control circuits (pen control, chart control, blanking), followed by replaceable parts lists and full schematics for the keyboard panel, control tray cards (0.12.1615, 0.12.1616), rep-op timer card (0.36.0192), mode control card (0.51.0357-1), and time scale rep-op card (0.51.0363-1).
- EAI 580 Console Chapter 7: The 0,10,0354 Power Supply
Chapter 7 of the EAI 580 Analog Computer console manual, covering the Model 0,10,0354 Power Supply in detail. The chapter describes electrical specifications (±30 V, ±15 V, ±10 V, ±5 V regulated outputs plus ±10.000 V reference), circuit operation of the series regulators and chopper-stabilized reference amplifiers, step-by-step adjustment procedures, and foldout schematics. Appendix 1 provides a complete replaceable-parts list with EAI part numbers for all printed-circuit cards in the power supply.
- 580/680 Scientific Computing System — Maintenance Series: 26.268 Digital Voltmeter
Maintenance manual for the EAI Model 26.268 Digital Voltmeter (DVM), a plug-in analog-to-digital conversion unit designed for the EAI 580/680 Scientific Computing System. The DVM provides a five-digit BCD successive-approximation readout over a ±10 V range (20% overrange to ±11.999 V) at 50 or 60 samples per second, with 500 MΩ minimum input impedance and ±0.01% full-scale accuracy. The manual covers physical description, installation, theory of operation (unloading amplifiers, comparator, gated resistor matrix, BCD counters, timing, and power supply), trouble analysis, calibration procedures, replaceable parts, and schematic drawings.
- Replaceable Parts List: Digital Voltmeter Model 26.268 and Display Unit Model 554.048 (Appendix 1)
Appendix 1 of the EAI 580/680 TDVM documentation, providing a complete replaceable parts list for the Digital Voltmeter Model 26.268 and Display Unit Model 554.048. Fourteen sub-assemblies are itemized with EAI part numbers and availability category (A: locally available; B: order from EAI), covering the main frame, dual DC amplifier, reference amplifier, miscellaneous and conversion delay networks, summing resistor network, comparator and diode gate, BCD decimal-decoding matrix/counter, power supply regulator, programmer, and readout display module. Dated 8/26/68 and issued by EAI Instrument Division, Long Branch, New Jersey.
- EAI-Report Nr. 014, 4. Jahrgang, März/August 1968
Customer newsletter (4th year, issue 14) from EAI Electronic Associates GmbH Aachen, covering product introductions and new developments across the EAI analog and hybrid computer line for March–August 1968. Highlights include the debut of the EAL-380 analog/hybrid desktop computer (10 V, 36 amplifiers, 400 kHz bandwidth, parallel logic), major EAI-680 enhancements (overload-limiting amplifiers, three-mode EMC integrators, 3-amplifier multiplier plug-ins, expansion system with resolver and coupling subsystems, teletype I/O station, and digitally controlled function generators), the EAI 8900 large hybrid system delivered to the UK's Central Electricity Generating Board, the Series 430 DataPlotter, EAI-640 digital computer installation at TU Berlin, and the European education and training programme.
- Analysis of Rolling Theory by Analog Computer — Karman's Differential Equation —
Technical Information Series No. 8 from Hitachi's Analog-Hybrid Computer line, demonstrating how an analog computer automatically solves Karman's differential equation to determine pressure distribution and rolling load during metal rolling. The document derives the governing equations (boundary-value problem, projected contact length, elastic deformation), describes the analog circuit design with five integrators and a program controller, and validates results against digital computer solutions across six parametric cases. Computation time is on the order of seconds versus minutes for digital approaches.
- Program Manual for Hitachi Analogue Computer — Automatic Programming (Technical Information Series No. 5)
Technical Information Series No. 5 from Hitachi, Ltd. covering automatic programming techniques for the Hitachi analogue computer. Describes logic operation circuits including memory elements, mode control circuits, boundary value analysis, extreme value analysis, and time-sharing computation. Includes worked exercises for each application type, aimed at operators who wish to automate repetitive parameter sweeps and optimization runs on the Hitachi analog-hybrid system.
- EAI 680 Analog Computer: Hybrid Computation Laboratory Users Manual
A concise 14-page users manual produced by the Carnegie-Mellon University Hybrid Computation Laboratory for the EAI 680 analog computer, dated September 1968. Covers the full workflow from problem preparation (problem statement, block diagram, scaling, computer diagram, static check) through patching and analog computer operation, with cautions and hints for safe use. Includes blank assignment sheets for potentiometers, amplifiers, logic components, and nonlinear components used in the CMU lab.
- Entwicklungstendenzen im hybriden Rechnen
German-language journal article by W. Giloi of the Technische Universität Berlin, originally presented as a lecture at the AFIPS Computer Exposition (Anaheim, November–December 1967) and published in Elektronik vol. 17, no. 11, 1968. The article surveys the state of hybrid computing as of 1967 — analyzing error behavior of analog versus digital computers, the structure of hybrid systems (ADC/DAC interfaces, crosspoint switch matrices, mode control), and emerging hybrid programming languages such as MIDAS, APACHE, and HYBLOCK. It concludes with a forward-looking prognosis for increasing automation of hybrid programming, larger reconfigurable analog networks, and the eventual migration of more computational work to the digital side.
- Analyse von natürlichem Modellseegang
A 1968 journal article (Schiffstechnik, Vol. 15, No. 75) by Dipl.-Ing. S. Kastner describing the design and construction of a special electro-mechanical analog analyzer for real-time spectral analysis of natural sea states during ship model stability tests. The instrument uses sine-cosine potentiometers driven by a synchronous motor to compute Fourier coefficients in the 0.25–1.5 Hz range (wavelengths 0.7–25 m), with 40 RC-integrator storage channels (τ = 1200 s, 4-minute integration cycles); the paper compares this approach to analog-computer filter circuits, digital methods, and drum-scanning techniques.
- Das Kentern von Schiffen in unregelmässiger längslaufender See
Doctoral dissertation published as Institut für Schiffbau Hamburg Bericht Nr. 249 (December 1968) by Sigismund Kastner, presenting a statistical-computational method for analyzing ship capsizing in irregular longitudinal seas. The nonlinear equation of rolling motion is solved using an analog computer, which the author justifies at length (Chapter 6) for its ability to handle nonlinear righting-lever curves directly, simulate oscillating systems without iteration, and dramatically compress computation time versus digital methods. Results include statistical distributions of time-to-capsize as a function of ship parameters such as metacentric height, damping, freeboard, and speed.
- PEAC: Practical Electronics Analogue Computer
A collected series of articles from Practical Electronics magazine describing the design, construction, and operation of PEAC (Practical Electronics Analogue Computer), a low-cost, general-purpose transistorised analogue computer intended for amateurs and students. The machine is organized into modular units (A through D) covering power supply, operational amplifiers, integrators, a function generator, and a four-quadrant multiplier, with a full PEAC installation costing around £60 circa 1968. The articles cover theory of analogue computing, circuit descriptions, programming techniques, and example problems including differential equations and mechanical system simulation.
- Zur numerischen Lösung von Randwertaufgaben des eingeschränkten Dreikörperproblems
A two-page offprint (Sonderdruck) from Luftfahrttechnik Raumfahrttechnik (Vol. 14, 1968, pp. 220–221) presenting a numerical method for solving boundary value problems in the restricted three-body problem (Earth–Moon–spacecraft). The authors use the AEG-Telefunken Rechenanlage BA 741 analog computer to compute minimum-flight-time trajectories for an infinitesimal body (spacecraft) between two circular orbits in the rotating coordinate frame. Two distinct trajectory solutions are found and illustrated graphically.
- Elektronische Analogrechner
Excerpt (pages 96–98) from the second edition of this German-language textbook on electronic analog computers, Volume 8 of the series 'Mathematik für Naturwissenschaft und Technik'. The excerpt covers Chapter IV on operational amplifiers, specifically §12 (complex-plane computing circuits) and §13 (reversible operational amplifiers), presenting mathematical derivations, node equations, and circuit configurations for reversible inverters, constant multipliers, and integrator-differentiators. Author Prof. Dr. Helmut Adler was Director of the Institute for Machine Computing Technology at the Technical University of Ilmenau; the full work contains 273 figures and 7 tables.
- Die Funktionsgleichungen des digitalen Integrators
German-language technical article by W. Zoberbier (1968) presenting the characteristic equations of the digital integrator, the fundamental component of the digital differential analyzer (DDA). The paper derives the operational equations governing the Y-register and Z-register modes, analyzes register boundary conditions and overflow handling, and provides synthesis rules for the critical circuit structure around the digital integrator. Applications to general-purpose computer implementation for rapid simulation are discussed.
- GAU's Analog Calculator: Multiply, Divide, Square, and Extract Roots
A reconstruction and machine-translated English version of a July 1968 article from the Italian magazine Sperimentare describing a simple battery-powered analog calculator built from three wire-wound linear potentiometers and a center-zero microammeter. The device performs multiplication, division, squaring, and square root extraction on numbers from 0 to 10 with approximately 5% accuracy by exploiting the potentiometric null-balance principle, making results independent of supply voltage. The article covers circuit theory, component selection, calibration procedures, operating instructions for all four arithmetic functions, and a retrofit modification using a trimmer and resistor to extend the division range by a factor of ten.
- Il calcolatore analogico di GAU: moltiplica, divide, eleva al quadrato ed estrae radici
A hobbyist article describing the construction and theory of a simple three-potentiometer analog computer originally published in the Italian magazine Sperimentare (July 1968, "Archimede, calcolatore elettronico") under the initials GAU. The device uses a 9 V battery, two 10 K and one 1 K wire-wound potentiometers, and a centre-zero microammeter to perform multiplication, division, squaring, and square-root extraction on numbers from 0 to 10 with approximately 5% accuracy. The reproduction adds a trimmer-and-resistor retrofit (DIV x10 mode) for quotients exceeding 10, provides step-by-step calibration and operating procedures, and derives the underlying potentiometric-bridge mathematics.
- Design of an Analog Computer
An Engineering Case Library case study (ECL 47) prepared at Stanford University documenting the design and product development of the Systron-Donner 10/20 analog computer. Written by Dick Dunlap, a product designer at Systron-Donner's Electronic Instrumentation division, the case traces the project from preliminary design in early 1963 through prototyping, pilot production, and the challenges of transitioning to full manufacture, covering design decisions, modular architecture, and cost-engineering trade-offs for a small, easily-portable computer aimed at the educational and light industrial markets.
- Optimierung eines Regelkreises mit Tischanalogrechner und Digitalzusatz
A 1968 Telefunken reprint (Sonderdruck) of an article from 'elektronische datenverarbeitung,' pp. 293–297, by H. Kramer. Describes how the Telefunken RAE 360 desktop analog computer, coupled with the DCR 100 digital attachment, is used to optimize a PID control loop by minimizing the quadratic integral criterion ∫e²(t)dt via an automated iterative hill-climbing algorithm. The digital unit systematically varies the three controller parameters (K_P, T_N, T_V), triggers simulation runs on the analog computer, and converges on the optimal parameter set without manual intervention.
- Das Hybride Rechnersystem HRS 900
A 1968 technical journal article by Ralf Schwarz, published in Techn. Mitt. AEG-TELEFUNKEN (3rd supplement, Datenverarbeitung), describing the AEG-TELEFUNKEN HRS 900 hybrid computer system. The system combines the RA 770 precision analog computer (with sub-computers RA 775 and RA 776), the hybrid coupling unit HKW 900, and the CII/SDS-licensed 90-40 digital computer (24-bit, 6 MHz, up to 32K words). The article explains the rationale for hybrid computing — filling the speed gap of digital computers in solving differential equations — and details the architecture of each subsystem including the digital programming field, timing circuits, servo potentiometers, and data-transfer mechanisms.
- EAI 580 Desk-Top Analog/Hybrid Computing System
Product brochure for the EAI 580 Desk-Top Analog/Hybrid Computing System, a fully solid-state 10-volt desk-top machine capable of up to 80 computing amplifiers and 8 comparator amplifiers. The brochure describes the system's master control panel, analog programming system, digital logic section (synchronous clocked logic with 32 gates, general-purpose registers, counter/timers), servo-set potentiometer system, system expansion options, and peripheral equipment. Application areas covered include analog/hybrid computation, iterative computation, full hybrid computation, bio-medical engineering, chemical process industry, aerospace, and education.
- EAI 580 Console Handbook — Chapter 4: Readout Selector System
Chapter 4 of the EAI 580 analog computer console handbook covering the Readout Selector System in full detail. The chapter describes the address select circuit (models 0.51.0359, 0.51.0360, 0.11.0213), all address-mode pushbutton switch circuits (DIG I/O, PP, F, D, D/10, P, A), the voltmeter (VM) null circuit and FUNCTION/RANGE switch functions, and the relay-matrix potentiometer readout scheme. Two appendices provide replaceable-parts lists with EAI part numbers dated October 1967 for seven card assemblies (Select Mother Card, Select Amplifier Network Card, Select Stabilizer Card, Monitor Panel, Voltmeter Card, Address Select Card, Units and Tens Select Card), plus an indexed set of schematics and wiring diagrams for the keyboard panel, select mother card, monitor panel, address select, units/tens select, and the 0.13.0046 Voltmeter Card.
- Servo and Handset Attenuators (EAI 580 Console Manual, Chapter 5)
Chapter 5 of the EAI 580 analog computer console manual, covering the servo and handset attenuator subsystem. A fully expanded 580 provides 70 motor-driven servo potentiometers (5K, ±1.0 mV setting error) addressed and set via a DAC keyboard, plus 10 manually set handset pots. The chapter details theory of operation, circuit descriptions for the 0.6.0677 Servo Amplifier Card and associated cards, maintenance and troubleshooting procedures, replaceable parts lists, and a complete set of schematics for all subsystem cards.
- EAI 580 Console Manual — Chapter 8: Power Distribution
Chapter 8 of the EAI 580 Console maintenance manual, covering the AC primary power distribution system (115 V / 230 V selectable via terminal board TB1 jumpers), the motor-driven patch panel engage/disengage drive system, and DC secondary power distribution via bus bars from the 0.10.0354 Power Supply. The chapter is followed by Appendix I (replaceable parts lists dated 10/11/67 for Motor Mounting, Dynamic Brake, OFF-ON DIS-ENG Card, Bus Bar Network Card, and Wired Cabinet) and Appendix 2 (drawings index and schematics for the Dynamic Brake and the OFF-ON/Dis-Eng Card, EAI drawing nos. 000 012 1092 IW and C10 012 1093 OW).
- EAI-Report Nr. 010 — Mitteilungsblatt der EAI Electronic Associates GmbH Aachen (Januar/Februar 1967)
Issue No. 010 of the EAI GmbH Aachen internal newsletter (January/February 1967) covers the company's German sales-territory reorganization for 1967 and announces scheduled analog and analog/hybrid computing training courses using the TR-48 and TR-48/DES-30. Technical content includes a detailed description of a sample-and-hold circuit technique for recording rapidly repetitive analog-computer runs point-by-point on a coordinate plotter, plus product notes on the new EAI 640 digital computer, the Brush Recorder Mark 250 strip-chart recorder, Poltron stabilized power supplies, and the EAI Variplotter X-Y recorder series.
- EAI-Report Nr. 011, März–April 1967
The March-April 1967 issue of the EAI-Report (No. 011), published by EAI Electronic Associates GmbH in Aachen, introduces the Series 6200 modular digital measuring system with detailed specifications for its DC integrating voltmeter (Series 6201), digital counter (Series 6202), and AC converter (Series 6203) plug-in modules. A technical article by Dipl.-Ing. K.H. Hortenbach describes an analog computer sample-and-hold circuit that exploits the parallel subroutine technique for efficient polar-to-Cartesian, Cartesian-to-polar, and coordinate-axis-rotation transformations, demonstrating substantial savings in nonlinear computing elements. The issue also covers the Brush logarithmic preamplifier for multi-channel recorders, Class B used-equipment availability (TR-48/58, TR-20), characteristics of the EAI 9000 hybrid scientific computing system, and a calendar of 1967 EAI events across Germany.
- EAI Report Nr. 012 — EAI 580 Analog/Hybrid-Rechner
Customer newsletter (Report No. 012, May–September 1967) from EAI Electronic Associates GmbH, Aachen, announcing the EAI 580 Analog/Hybrid Computer: a desktop system with 80 computing amplifiers, 70 servo potentiometers, ±10 V reference, ±0.01% linear accuracy, built-in parallel logic, and interface for coupling to digital computers (EAI 640, PDP-8-S), priced between DM 50,000 and DM 250,000. The report also includes a historical timeline of EAI analog and hybrid systems from 1948 to 1967, information on the Brush MARK 220 two-channel recorder, new EAI digital voltmeter models (6240 rack-mount and 6250 TR-10/TR-20 accessory), and details of the December 1967 EAI Analog/Hybrid Computing Course with full curriculum.
- EAI Analog/Hybrid-Rechner Newsletter Nr. 013, Oktober 1967 – Februar 1968
Quarterly German-language customer newsletter from EAI Electronic Associates GmbH (Aachen), covering October 1967 to February 1968. The featured technical article details the analog computer simulation of the pumping action of the left cardiac ventricle on the EAI 580, including patch diagrams and oscillograms for normal and pathological heart behaviour (valvular insufficiency, stenosis). Additional content describes new plug-in modules for the EAI 580, the Series 10 special-purpose analog data processor, Brush Mark 26C 6-channel recorder, Variplotter 1140 M XY plotter, EAI's role in the Apollo re-entry simulation on the EAI 690, a TR-20 fruit-tree dynamics simulation at Rutgers University, and scheduled analog/hybrid training courses for early 1968.
- TR-20 Computer Maintenance Series
Comprehensive maintenance manual for the EAI TR-20 analog computer, published August 1967 (Publ. No. 00 800.2006-0). The manual provides chapter-by-chapter circuit descriptions, technical data, patching procedures, test procedures, and troubleshooting guidance for every major TR-20 computing element including the dual DC amplifier (Model 6.712), dual integrator network (Model 12.1116), quarter-square multiplier (Model 7.045), diode function generators (X², log X, variable), coefficient attenuator groups, signal comparators, repetitive-operation and manual-mode control circuits, and regulated power and reference voltage supplies. Four appendices cover elementary analog-device principles, transistor and etched-board servicing techniques, replaceable parts lists, and engineering drawings.
- HITACHI Analog-Hybrid Computer Technical Information Series No.2: Information on Hybrid Interface (2nd edition)
This Technical Information Series No.2 (2nd edition) provides detailed specifications for linking the HITACHI-505 analog computer to a digital computer via a hybrid interface. It covers interface signal requirements, input/output channel configurations, multiplexer and A-D converter performance specs (±10V range, 0.1% accuracy, sign+binary 10-bit output code), and the serial BCD protocol for remotely setting servo-set potentiometers (SP) and servo-set function generators (SFG) from the digital side. Connector pin-out tables and system block diagrams for the hybrid linkage are included.
- Additional Elements of Hitachi 505 Necessary for Hybrid Computing System
Technical Information Series No. 1 (2nd edition) from Hitachi, Ltd., describing the additional hardware elements required to upgrade the Hitachi 505 analog computer into a hybrid computing system. Covers the hybrid linkage configuration, voltage comparator CP-153, servo-set potentiometer panel SP-251, servo-set function generator panel SFG-251, selector-setter panel, and servo-set console, along with signal specifications for D/A and A/D converters, external control inputs, clock signals, and interlock control between the analog and digital subsystems.
- Technical Information Series No. 3: Double Integral (Calculation of Volume of Cone)
This application note demonstrates the use of a Hitachi analog-hybrid computer to evaluate a double integral for calculating the volume of a cone using multiple time axes. The computation slices the cone into N thin cylindrical sections (N=250 for the calculation, N=25 for reference), summing the cross-sectional areas iteratively; results are displayed via pen recorder and pattern display on oscilloscope showing the three-dimensional cone surface. Computing elements required include dual DC amplifiers (DA-151/DA-151A), dual integrators (IN-151/IN-153), potentiometer panels (PT-251/PT-151), voltage comparators (CP-151/CP-152/CP-153), and a square function generator (FG-154A).
- An Application of Hybrid Curve Generation: Cartoon Animation by Electronic Computers
Conference paper from the 1967 Spring Joint Computer Conference describing two hybrid-computer methods for automating cartoon animation. The analog method generates pictures on a CRT by modifying circles via transformation circuits on the Hitachi ALS-2000; the hybrid method reads animator-drawn keyframes into a digital computer, calculates tangents by parabolic approximation, and uses analog elements to interpolate smooth curves between frames. Mathematical details of both linear and similarity-based frame interpolation are provided.
- A New Digital-Attenuator System for Hybrid Computers
NASA Contractor Report CR-87287 describing a digital attenuator system for analog/hybrid computers, developed at the University of Arizona's Analog/Hybrid Computing Laboratory. The system uses miniature metal-film ladder networks switched by latching reed relays for nondestructive coefficient memory, with serial data transmission allowing all 200 attenuators of a typical hybrid computer to be set within 20 milliseconds. The design replaces conventional servo-driven potentiometers to dramatically reduce problem setup time.
- Study of Electrical Analogue for Electrodialysis
Office of Saline Water Research and Development Progress Report No. 238 (February 1967), prepared by the Astropower Laboratory of Douglas Aircraft Company. Develops a mathematical electrical-network analogue model of the electrodialysis desalination process, decomposing each stage into resistive sub-elements (concentration polarization, ohmic polarization, membrane resistance, electrode polarization, and parasitic duct losses). Applies the model to operating plants at Webster, South Dakota and Buckeye, Arizona, achieving agreement within 94% of measured stack resistance, and projects 15-45% resistance reductions through improved hydrodynamics and advanced membranes.
- Handbook of Analog Computation
A comprehensive second-edition handbook developed by the EAI Education and Training Department from nearly a decade of intensive short courses in analog computer operation, programming, and applications. The 396-page volume covers the full spectrum of analog computation: linear and nonlinear components, scaling and programming procedures, function generation, transfer-function simulation, transport delay, repetitive and memory operation, partial differential equations, accuracy analysis, and efficient programming case studies. Machine-specific examples reference the PACE TR-20, PACE TR-48, and large-scale EAI 8800 systems, with appendices on Laplace transforms, transfer-function circuits, diode/relay circuits, and an applications bibliography.
- Handbook of Analog Computation (Including Application of Digital Control Logic)
A comprehensive 163-page handbook prepared by Maxwell C. Gilliland (Computer Research, Inc.) and Systron-Donner staff covering analog computation from fundamentals through advanced applications. The 22 chapters span basic computing elements, analog programming techniques, scaling, computer operation, digital control logic, partial differential equations, control system simulation, vector analysis, sampled-data systems, correlation analysis, system optimization, medical applications, and adaptive control. Intended for Systron-Donner analog computer users and seminar participants.
- Elektronischer Resolver ERV 801 — Informationsblatt AiB 010
Two-page German-language information sheet (Informationsblatt AiB 010) for the AEG-Telefunken ERV 801 Electronic Resolver, published 1967. Covers application (polar-to-Cartesian and Cartesian-to-polar coordinate transformation, multiplication, and inverting-amplifier modes selectable by front-panel key), outstanding features (modular plug-in construction, wideband Hall-effect multipliers), and full technical specifications including static errors (sin/cos ≤ 0.1 %, magnitude ≤ 0.2 %, angle ≤ 0.03 %), bandwidths (up to 110 kHz), power supply (220 V / 30 VA), and physical dimensions.
- EAI 580 Analog/Hybrid Computing System — Maintenance Series: Computing Components
This maintenance manual covers the computing components of the EAI 580 Analog/Hybrid Computing System, including dual and quad DC amplifiers, integrators, summing integrators, quarter-square multipliers, diode function generators, potentiometer-comparator-function relay trays, track/store units, DG switches, and logic interface circuits. Each section provides technical data, theory of operation, circuit description, maintenance and adjustment procedures, replaceable parts lists, and schematics. Published by Electronic Associates, Inc. in May 1966 (Publication No. 00 800, 5020-A).
- 680 Scientific Computing System Reference Handbook
This reference handbook covers the EAI 680 Scientific Computing System, a large-scale analog/hybrid computer. It describes all computing components in textbook format, including combination amplifiers, summers, servo-set potentiometers, multipliers, fixed and variable diode function generators, comparators, logic trays, and the patch panel layout. A fully expanded 680 features 156 amplifiers, 120 servo-set pots, 24 multipliers, 18 variable DFGs, and 24 comparators; the handbook guides programmers from machine organization and the signal selector system through mode control, time scale selection, and appendices on specific applications and scaling techniques.
- Stored Program Concept for Analog Computers
This final report, prepared by EAI Applications Engineer George Hannauer for NASA's George C. Marshall Space Flight Center (EAI Project #320009, NASA Order #NAS8-21228), investigates the feasibility of implementing a stored-program concept for analog computers using electronic switching matrices. The report develops mathematical theory for multi-stage crossbar switching networks -- analyzing three-stage matrices with and without fanout, modular analog configuration design, and switch-assignment algorithms -- then demonstrates the concept against NASA simulation problems including Voyager first-stage ascent and Saturn IV stage control. Software routines for switch assignment, matrix terminal assignment, interconnection, and component assignment are also described.
- Mitteilungsblätter EAI Electronic Associates GmbH, Nr. 005 (Jan.–Febr. 1966)
Issue No. 005 of the EAI Electronic Associates GmbH (Aachen) customer newsletter for January–February 1966, written in German. The newsletter covers the Brush Mark 280 two-channel ink recorder (35 Hz bandwidth, 0.5% accuracy, 80 mm channel), squaring and square-root circuit configurations using EAI parabola multipliers on the TR-48 and TR-20 with a detailed table of wiring options, and a technical introduction to the DES-30 Digital Extension System for hybrid computing with TR-20 and TR-48 analog computers. Additional items include announcement of 1966 analog computing courses in Aachen, the MC laboratory connector system, Heinzinger high-voltage power supplies, and the EAI high-speed printer type 6.610.
- Mitteilungsblatt der EAI Electronic Associates GmbH, Nr. 008, Juli–August 1966
Issue No. 008 (July–August 1966) of the EAI Electronic Associates GmbH customer newsletter announces analog computer training courses in Aachen for October and November 1966, and reports on the EAI Symposium held in Munich in June 1966 covering TR-48/58, DES-30, and hybrid systems. The bulletin also introduces six new VARIPLOTTER X-Y recorders (Types 1120–1133, DIN A3/A4 formats) and the new Series 6.681 compact computing amplifiers (four variants: high-speed op-amp and differential DC amp, ±15 V supply, 25 mA output, epoxy-encapsulated at 52×25×25 mm), with full specification tables and DM pricing. Class-B (refurbished) PACE TR-48 and TR-20 systems are noted as available for purchase.
- EAI Mitteilungsblatt für Kunden und Freunde der EAI Electronic Associates GmbH — Nr. 009, September/Oktober 1966
Customer and dealer circular issued by EAI Electronic Associates GmbH (Aachen) for September–October 1966, announcing participation at the Electronica 66 trade fair in Munich. The newsletter introduces the EAI 680 analog/hybrid computer (fourth-generation hybrid, 10 V reference, up to 156 amplifiers, 4080-hole patchboard, fully transistorized, 150×150×75 cm, no air conditioning required), describes the new all-solid-state VARIPLOTTER 1133 M coordinate recorder (28×43 cm, ±0.2% accuracy, 50 cm/sec slew rate, DM 6,255), and lists new logarithmic and AC input modules for the VARIPLOTTER 1110, along with prices, Class B used-equipment availability, and an EAI event calendar.
- EAI Mitteilungsblatt Nr. 7 — Mai/Juni 1966
The seventh issue of EAI's German-language customer newsletter (May–June 1966) covers three main topics: a technical description of the PDS 1020 general-purpose digital computer including its magnetostrictive delay-line memory, seven-register architecture, and INTERPRETER software; a detailed technical article on iterative computing methods for analog computers using track-store (sample-and-hold) units for analog point storage; and company news including the use of the EAI PC 12 process computer in the Surveyor Moon-landing mission, Class-B used equipment availability, and EAI delivery milestones for TR-series machines.
- Schaltungen der Analogrechentechnik
A collection of 95 fully derived and practically tested analog computing circuits by Dipl.-Ing. W. Ammon, published as Band 9 of the supplement series to the journal 'Elektronische Rechenanlagen' (R. Oldenbourg, Munich/Vienna, 1966). The 146-page book covers rational transfer functions, dead-time simulation, division, square roots, trigonometric functions, coordinate transformations, sine/cosine generation, hysteresis curve simulation, pulse generation, samplers, and diode function generators, illustrated with 172 figures. Circuits are derived primarily for EAI TR-10/TR-48 and Telefunken RA 770 but are broadly applicable to any analog computer with standard components.
- Der Transistorschalter im analogen Rechenkreis
A 6-page German-language technical article (Elektronische Rechenanlagen, 1966) by E.V. Gilles and H. Schuchmann of the Rechenmaschinen-Laboratorium at Technische Hochschule Stuttgart. The paper analyzes transistor switches (Transistorschalter) used in analog computing networks for solving partial differential equations iteratively, covering switching requirements, transistor parameters (saturation voltage, leakage current, transition frequency fT), and a practical complementary emitter-follower circuit design. Measured results and a comparison table of key switch parameters are provided.
- Zur Steuerung von Analogrechenschaltungen
A 1966 German academic article from the Institut für Angewandte Mathematik at Technische Hochschule München, presenting switching-control methods for sequencing analog computer programs. The authors (Heinhold and Kulisch) describe how a matrix-based digital control unit can manage the compute/halt/initial-condition phase sequence of analog integrators, including branching on comparator outputs for iterative convergence and multi-segment computations. Published in Elektronische Rechenanlagen, Vol. 8, No. 5, pp. 231–235, it anticipates the digital-control architectures of hybrid computers.
- A Discussion of Proposals by Vendors for the Hybrid Simulation Equipment for the C-3 Project (LMSC)
Transcription of a March 1966 presentation by J. E. Sherman, Manager of Analog and Hybrid Computing at LMSC, to approximately 40 personnel covering the selection process for a hybrid computing center in Building 181 for the C-3 Project. The document evaluates proposals from Electronic Associates Inc. (EAI), Astrodata, and Beckman, and includes charts describing the hybrid system concept (analog computer + interface + digital computer) and a proposed configuration with dual CPUs sharing 48K common storage connected via interfaces to four analog computers. Serves as an internal procurement evaluation record.
- Hybrid Computer System Request for Proposal
A January 1966 Request for Proposal (RFQ) issued by Lockheed Missiles & Space Company (LMSC) for the procurement of a hybrid computer system. The document defines detailed technical requirements for the analog section, covering minimum component counts for five identical computing systems, including operational amplifiers, integrators, summers, potentiometers, multipliers, resolvers, and electronic switches. Intended to solicit competitive bids from computer manufacturers for a high-accuracy hybrid computing facility to support Lockheed's aerospace simulation work.
- Stability Research on Parachutes Using Digital and Analog Computers
NASA technical translation (TT F-10,391) of a 1963 German conference paper by R. Ludwig, presented at the International Symposium on Analog and Digital Techniques Applied to Aeronautics in Liege, Belgium. The paper investigates the dynamic stability of parachutes using nonlinear equations of motion solved on both digital computers (IBM 650, Siemens 2002, using Runge-Kutta) and an analog computer, covering approximately 80 computed cases. It demonstrates that linearization is fundamentally inadequate for describing parachute oscillation dynamics and that analog and digital computation together are essential for this class of nonlinear flight mechanics problems.
- Hinweise zum Entwurf von Digitalen Schaltwerken bei der Lösung von Optimierungsaufgaben mit dem Analogrechner
A German-language technical article by H. Schrimpe describing the design of digital sequential networks (flip-flop logic) to control analog-computer-based parameter optimization on the AEG-Telefunken DEX 102 (DEX 100) analog computer. The paper derives Boolean switching equations from a flow diagram for one-dimensional optimization with step-size control, uses Karnaugh-Veitch diagrams for logic minimization, and presents the resulting flip-flop control circuits for integration with the analog machine run/hold modes.
- Demonstrationsbeispiele fur Analogrechner RAT 740 — Beispiel 2: Einfache Darstellung einer Planetenbahn
A short German-language application note (3 pages, dated 1 November 1966) from Telefunken's Analog Computer Department, presenting Example 2 in a series of demonstration programs for the RAT 740 analog computer. The document describes a simplified simulation of planetary orbital motion using Kepler's laws: an elliptical orbit is generated via sine-cosine function generators and multipliers, with the orbital eccentricity and semi-axis adjustable via potentiometers, and the result displayed on an oscilloscope as a Lissajous figure. Page 3 contains the full patching/wiring diagram for the RAT 740 implementing this circuit.
- Anwendungsbeispiele für Analogrechner – Beispiel 6: Beschaltung von Parabelmultiplizier-Netzwerken
Application example 6 in the Telefunken analog-computer application series, dated 22 April 1966, covering parabola multiplier network circuit configurations for the RAT 700, RAT 700/2, RAT 740, RA 741, RA 800, and RA 800 HYBRID machines. The 33-page document provides programming panel wiring diagrams and schematic circuits for multiplication, division, square-root extraction, square root of products and sums of products, multiplication with simultaneous addition, and special multiplier configurations. Each operation is addressed machine-by-machine with both symbolic block diagrams and detailed patch-panel connection drawings.
- Telefunken Zeitung — Jahrgang 39, Heft 1 (1966)
The Telefunken Zeitung, Year 39, Issue 1 (February 1966), is Telefunken AG's in-house technical journal containing multiple articles on analog and hybrid computing technology. The issue covers the state and development of analog and hybrid computers (by Meyer-Brötz, Klug, Grau, and Haußmann), applications of hybrid computing techniques to analog computing elements, and detailed descriptions of the Telefunken RA 770 and RA1 770 analog computers, along with articles on computing amplifiers, multiplexed operation with semiconductor elements, and error analysis in computation.
- EAI 680: A Hybrid Computer to Grow With
A 12-page product brochure (Bulletin No. AC65064, September 1965) from Electronic Associates, Inc. describing the EAI 680 Scientific Computing System, a hybrid analog-digital computer. The brochure covers applications across process industries, universities, life sciences, and aerospace, and highlights hybrid capabilities including electronically addressed servo-set potentiometers, parallel digital logic, 500 kc bandwidth operational amplifiers, and track/store units with sub-microsecond reset. The console houses up to 156 amplifiers, 120 potentiometers, quarter-square multipliers, and variable diode function generators in a compact 5 x 5 x 2.5 foot welded steel frame operating on 10-volt solid-state circuitry.
- Investigation of Heat Transfer by Conduction
A two-page EAI educational applications note (Bulletin No. ALAC 64135) describing the analog simulation of one-dimensional heat conduction through a metal rod on the PACE TR-20 General Purpose Analog Computer. The system is modeled using a second-order central-difference approximation to the diffusion equation, dividing the rod into five equally spaced segments to yield a set of scaled ordinary differential equations. The note provides system equations, a computer diagram, and potentiometer and amplifier assignment sheets.
- Modelling Dynamic Economic Problems on an Analog Computer
This EAI bulletin (No. ALAC 65087) by Alfred Engel and John J. Kennedy presents the theory and mechanization of dynamic economic models on analog computers, contrasting analog-friendly continuous differential-equation approaches with finite-difference sequence models. It covers non-genuine and genuine lags, open systems, forced-goal (boundary-value) problems, policy-decision mechanization using comparators and function switches, and the use of track-and-store amplifiers and VDFGs — illustrated with circuit diagrams for Samuelson's Second Interaction Model and Leontief's two-sector lag system. The EAI TR-20, PACE 231R-V, and HYDAC 2400 hybrid system are cited as representative hardware.
- EAI-Report Nr. 001 — Mitteilungsblatt der EAI Electronic Associates GmbH
The inaugural issue (July 1965) of the EAI-Report, a German-language product newsletter from EAI Electronic Associates GmbH Aachen. It announces EAI's new exclusive distributorship for Germany, describes a modification enabling individual operating-mode control (Reset/Hold/Operate/Time-Scale) on TR-10 integrating networks, and details numerous improvements to the TR-48/58 desktop analog computer including a 58-amplifier configuration, improved multipliers, variable-breakpoint function generators, delay-line and reactor-kinetics networks, fast comparators, and the new DES-30 digital extension system.
- EAI Mitteilungsblatt Nr. 002 — August 1965
An eight-page German-language customer newsletter (Mitteilungsblatt) from EAI Electronic Associates GmbH Aachen, dated August 1965, covering general announcements (office expansion, trade show appearances, analog computing course), technical announcements for the EAI-8875 multi-channel rectilinear recorder (12 paper speeds, forced-fluid ink system, up to 8 channels), the Electronic Mode Control (EMC) upgrade option for the TR-48/58, and the new Type 1026.003 transistorised digital multimeter. Also introduces the PDS 1020 general-purpose digital computer (magnetostrictive delay-line memory, 2,048 words, variable word length 4–24 digits, under DM 100,000) and provides updated DM price lists for TR-20 and TR-48 accessories and the 8875 recorder series.
- EAI Mitteilungsblatt Nr. 004 — November 1965
Monthly newsletter (No. 004, November 1965) from EAI Electronic Associates GmbH (Aachen), announcing EAI's new distribution of Brush Instruments recording systems in West Germany, providing specifications for the VARIPLOTTER Type 1110 XY recorder (28x43 cm format, 0.075% static accuracy), listing stock-available TR-20 and TR-48 Class B analog computers, and advertising new features of the TR-48 including hybrid operation with the DES-30 digital expansion system and expansion to 58 computing amplifiers. Also includes a product listing for Josef Heinzinger high-voltage power supplies and MC laboratory cable accessories.
- Untersuchungen über den Einfluß der Tanklage und nichtlinearer Dämpfungseffekte auf die Wirkung eines Schlingertanks
Technical report (Bericht Nr. 155) from the Institut für Schiffbau der Universität Hamburg investigating the influence of tank vertical position and nonlinear damping effects on the effectiveness of a Frahm-type passive anti-rolling tank aboard ships. The study develops dimensionless equations of motion coupling ship roll, tank water motion, and lateral (sway) motion, then uses an analog computer to simulate the nonlinear system and study parametric variations affecting roll amplitude reduction. Results show that positioning the tank above the ship's center of gravity improves anti-rolling effectiveness, and that optimal tank parameters depend substantially on ship form and heading angle.
- Simple Analogue Computer
A 7-page construction article by H. Webster describing how to build a simple analog computer based on a Wheatstone bridge circuit using calibrated potentiometers. The computer performs multiplication, division, evaluation of powers and roots, and logarithmic scaling. Covers circuit description, printed wiring board construction, calibration procedures, and a components list.
- Führungsverhalten des vierrädrigen Straßenfahrzeugs bei Regelung des Kurses auf festgelegter Bahn
A 6-page German journal article (Regelungstechnik, Vol. 13, No. 5, 1965) analyzing the guidance behavior of a four-wheeled road vehicle under automatic course control. Drawing on Fonda's vehicle differential equations and classical control theory, the author derives transfer functions for lateral and yaw dynamics, compares mechanical/optical/electrical guidance systems, and shows via analog computer simulation that a lateral-deviation controller is poorly damped. A new controller architecture using curvature difference as the primary control variable eliminates the destabilizing 1/p² geometry element and achieves acceptable stability; FM modulation of the guidance cable supplies curvature set-point information to the vehicle.
- Electronic Analog Computer Primer
An introductory textbook on electronic analog computers by James E. Stice (University of Arkansas) and Bernet S. Swanson (Illinois Institute of Technology), published by Blaisdell Publishing Company in 1965. The book serves as a primer covering the principles, components, and operation of electronic analog computers, intended for students and engineers new to the field. It is part of the Blaisdell Pure and Applied Sciences series, with Leon Lapidus of Princeton University as consulting editor.
- Continuous Data Analysis with Analog Computers Using Statistical and Regression Techniques
This EAI bulletin (ALAC 62023) demonstrates how fundamental statistical parameters — mean, variance, autocorrelation, cross-correlation, Fourier transform, and power spectrum — can be computed continuously from analog signals using the Exponentially Mapped Past (EMP) method and simple first-order filter circuits. The EMP approach eliminates the need to reset integrators by weighting recent data more heavily, enabling truly continuous on-line estimation. Linear and higher-order regression analysis is also developed, with a worked example applying EMP mean and variance to automated temperature control in the LD steel-making process.
- System Response Analysis with the Analog Memory and Logic System
This EAI application note (Bulletin No. ALHC 64024) describes techniques for analyzing system response characteristics using a general-purpose analog computer equipped with EAI's Analog Memory and Logic System. The document covers three operating modes—real-time simulation, compressed time-scale, and high-speed operation—along with a stroboscopic plotting technique using analog memory units for recording high-speed repetitive solutions and a probability distribution analysis technique using Gaussian noise input.
- The Simulation of Transport Delay with the HYDAC Computing System
This two-page EAI bulletin (No. ALHC 64019, 1964) describes a hybrid computing technique for simulating transport delay on the HYDAC Computing System using analog-to-digital conversion, digital function storage, and logic components. The program supports up to ten independent delay channels with storage capacities of 16, 64, or 256 words per channel and variable delay times, overcoming the phase-error and multiplier-count limitations of classical Pade-polynomial analog approaches. Sample results for two-channel transport delay with a velocity step change are presented.
- PACE TR-20 / TR-48 Desk Top Analog Computers
A six-page color sales brochure from Electronic Associates, Inc. (EAI) promoting the PACE TR-20 and TR-48 desk-top analog computers. The TR-48 features up to 48 amplifiers, the widest usable bandwidth of any desktop computer, high-speed repetitive operation (100 to 5000:1 time-scale change), solid-state readout, removable color-coded patch panels, and low-power compact design operating from 115/230 V at 50/60 Hz. The TR-20 is a portable fully transistorized 15" x 27" unit with up to 20 amplifiers, interchangeable non-linear computing components, variable diode-function generators, and an inclined color-coded patch panel; typical applications listed for both machines span aerospace guidance, nuclear reactor simulation, chemical kinetics, biomedical modeling, and geophysical analysis.
- TR-20 Computer Operator's Reference Handbook
This handbook serves as an operator reference guide for the EAI TR-20 desktop analog computer, covering operating considerations, computing components, and patching procedures. It describes the operational amplifier, attenuators, quarter-square multiplier, diode function generators, variable diode function generators, signal comparators, function switches, and repetitive operation mode. Appendices provide computer symbols, circuits using computational components, amplifier circuits for simulating transfer functions, and a bibliography.
- CANDIDE: Overall Plan for Possible Developments of Linkage of the CETIS Analog and Digital Computers
NASA Technical Translation TT F-8591 (January 1964) of the 1963 EURATOM/CETIS report No. 33 by A. Riotte. The paper presents an overall development plan (project CANDIDE) for linking the CETIS analog and digital computers at the Joint Nuclear Research Centre, Ispra, Italy. Two linkage types are addressed: one-directional static linkage placing the analog computer under digital control via the APACHE programming code, and dynamic two-directional linkage using A/D and D/A conversion so the digital computer acts as a real-time function generator. Planned subprojects SATANAS and ATANASE are outlined, along with ancillary studies on automatic scaling, subroutine libraries, and time estimates for each development stage.
- Nachbildung der Saturn V-Rakete auf elektronischen Analogrechnern
Conference proceedings article No. 29 from the 13th Hermann Oberth Society Rockets and Spaceflight Conference (Darmstadt, June 1964). Dipl.-Ing. D.L. Teuber describes how a high-speed GPS analog computer operating in repetitive mode was used to simulate the Saturn V rocket's dynamic behavior with 12 degrees of freedom, accounting for fuel sloshing and bending oscillations. A key contribution is the statistical analysis of atmospheric wind disturbances as stochastic inputs, using both measured wind data on magnetic tape and noise-generator-based synthetic wind profiles, enabling thousands of solutions to be evaluated in minutes to optimize Saturn V control parameters.
- Analogue Tutor TY1351 Instruction Manual
Instruction manual for the Solartron Analogue Tutor TY1351, a bench-top operational amplifier computer designed specifically for educational use in training students on analog computation techniques. Covers circuit description, amplifier circuitry (including summer/integrators, reference supplies, and the AS1403 Power Supply Unit), initial checkout procedures, and a list of components. Published May 1964 by The Solartron Electronic Group Ltd., Farnborough, Hants.
- Dual Operational Amplifier Type AA1054.2 — Instruction Manual
Instruction manual for the Solartron AA1054.2 Dual Operational Amplifier, a plug-in unit housing two independent general-purpose DC operational amplifiers for summing, integrating, or inverting operations. Covers electrical specifications (output ±100 V, DC gain >10^7, input current <10^-10 A, bandwidth ≥5 kc/s at gain of 10), installation and operation with the TX1055.2 six-unit mounting rack, circuit description, test procedures, and a component list. Issue One, dated May 1964; Mod. Ref. 1054.2/15 and 1053.2/15.
- Arithmetic Operations with the HYDAC Digital Operations System
This bulletin (ALHC 6388-1) describes how the general-purpose logic components of the EAI HYDAC Digital Operations System (DOS) are configured to perform binary arithmetic: half and full adders, half and full subtractors, serial and parallel adder-subtractor units, and serial and serial-parallel binary multipliers. Boolean expressions, truth tables, and DOS patch-panel programs are presented for each circuit, along with the Adder-Subtractor Group building block that reduces patching effort for repetitive operations.
- Flow Rate Computation: Automatic Dumping Hoppers
A one-page application note (EAI Bulletin ALMP6369-1ob, 1963) describing the use of an EAI PC-12 Process Control Computer to compute flow rates from automatically-dumping hoppers in grinding mill operations. A simple analog circuit computes individual product rates (R = W/t) and fractional production rates, giving mill operators real-time feedback for adjusting grinding parameters. The note includes a circuit diagram for the dumped-hopper computing circuit.
- Hybrid Computing at Ames Research Center: The Ames Linkage System and the Digital Logic Simulator
NASA Technical Memorandum TM-X-50975 from Ames Research Center describes two hybrid computing systems developed at the Center: the Ames Linkage System, which couples a remote analog simulator to a digital computer over 2500 ft of coaxial transmission lines for reentry vehicle flight simulation, and the Digital Logic Simulator (DLS), a general-purpose logic computing element placed in service September 1962. The paper details the Data Acceptance Routine (DAR) for efficient time-sharing of the digital computer between production work and simulation runs, and presents three DLS applications including heartrate computation from ECG data and probability distribution determination using hybrid techniques.
- Programming an Analog Computer for a Large Class of Trajectories
Technical report TR-1146 from Harry Diamond Laboratories (U.S. Army Materiel Command), dated 20 June 1963. Extends the negative gradient (steepest descent / transpose matrix) method to stable analog computer programming of a broad class of time-varying trajectory problems defined by coupled position and velocity vector equations. Defines an augmented velocity function vector, partitions the problem into reset-mode initialization and compute-mode integration, derives the characteristic matrix differential equation, and establishes stability conditions involving time scaling and gain reduction.
- Anwendungsbeispiele fur Analogrechner, Beispiel 1: Einige spezielle Kunstschaltungen bei Benutzung des Tischanalogrechners RAT 700
A 7-page German-language application note (dated 15 October 1963) for the Telefunken RAT 700 desktop analog computer, labeled Beispiel 1 (Example 1) in a series of application examples. It presents special Kunstschaltungen (special circuit configurations) including differentiation with a low-pass limiting network, parabolic multiplication to compute Ye²/2 or sign(Ye)·Ye²/2, and square root extraction yielding Ya = Ye/√|Ye|, each illustrated with circuit diagrams and RAT 700 patch-panel wiring diagrams.
- Anwendungsbeispiele für Analogrechner — Beispiel 3: Zwei-Massen-System
Application example 3 from TELEFUNKEN's 'Anwendungsbeispiele für Analogrechner' series (15 October 1963), demonstrating analog computer simulation of a coupled two-mass spring-damper system subjected to a step disturbance. The document derives normalized equations of motion, specifies system constants (m₁=20 Kp s²m⁻¹, c₁=1000 Kp m⁻¹, etc.), presents the analog patch diagram, and shows three cases: linear (a), asymmetric damper (b), and piecewise-linear spring (c), with oscilloscope result traces for each case.
- Anwendungsbeispiele für Analogrechner: Beispiel 4 — Erwärmung eines Kabels (Wärmeleitung)
Example 4 in Telefunken's 'Application Examples for Analog Computers' series, dated 15 October 1963. It demonstrates how to simulate radial heat conduction in cylindrical cable insulation on an analog computer: the partial differential equation is reduced to a system of eight coupled ordinary differential equations via finite differences (five radial steps), normalized, mapped to a chain of potentiometer-fed integrators, and solved. Results are presented as time-domain temperature curves at each radial node and as spatial temperature profiles at fixed times.
- Anwendungsbeispiele für Analogrechner — Beispiel 5: Transformator
A 6-page Telefunken application example (Beispiel 5, October 1963) showing how to simulate a power transformer on an analog computer, including a nonlinear iron-core magnetization characteristic. The document derives normalized differential equations for both ohmic-inductive and ohmic-capacitive loads, presents the analog computing circuit using the implicit (open-amplifier) method, and shows computed waveforms of primary and secondary currents at switch-on.
- Anschreiben: HYDAC Digital-Analog Computer Series 2000 (EAI European Division an Prof. Dr. K. H. Weise)
A one-page sales letter in German dated 28 June 1962 from Hans H. Brüggemann, Sales Engineer at EAI Electronic Associates Inc. European Division (Brussels), addressed to Prof. Dr. K. H. Weise at Kiel University. The letter introduces the HYDAC Digital-Analog Computer Series 2000, noting that the standard PACE 231R analog computer is a core component and that existing PACE 231R installations can be upgraded into a full HYDAC hybrid system. A product brochure and a data sheet for the Microstore Model 2.395 are mentioned as enclosures.
- A Practical Approach to Analog Computers
An 11-page introductory article, reprinted from Instruments & Control Systems (Vol. 35, No. 8, August 1962) and issued as EAI Applications Reference Library Computing Techniques 1.8.1, that explains analog computation to engineers unfamiliar with the field. It covers the basic building blocks of general-purpose analog computers—high-gain amplifiers, summing amplifiers, potentiometers, integrators, servomultipliers, and diode function generators—and demonstrates how to translate differential equations into patch-panel programs, using a simple pendulum problem as a worked example. The PACE 231R computer is illustrated as the representative hardware platform throughout.
- Engineering Applications of Analog Computers
ANL-6319 Rev. is an Argonne National Laboratory report presenting seven worked engineering experiments solved on analog computers, covering reactor control rod deceleration, pressure flow through packed beds, reactor kinetics with thermal feedback, vibrating systems, temperature distribution in fins and slabs, and iodine-xenon buildup in a reactor. Each experiment follows a structured format covering problem description, mathematical statement with constants and initial conditions, machine equation derivation with scale factors, circuit diagrams with potentiometer and static check sheets, and graphical results. The document demonstrates direct analog solution of nonlinear differential equations from nuclear reactor engineering and heat transfer without linearizing simplifications.
- An Analog Computer Model of a Multiple-Region Reactor
ANL-6482 is a 1962 Argonne National Laboratory technical report describing an analog computer technique for solving the time-space-dependent neutron diffusion equation for a multiple-region reactor. The method handles fuel burnup, fission product and xenon-iodine poison buildup, and control poison injection while maintaining constant power, using interregion neutron diffusion expressed as a surface integral to achieve accurate flux plots with only six spatial points. Complete circuit diagrams, potentiometer settings, scaled equations, and comparison with digital results are provided.
- Etude sur Simulateur des Régimes Transitoires des Concentrations dans une Installation de Diffusion Gazeuse
CEA Report No. 2010, authored by Delarousse, Trouvé, and Jacques from the Uranium Isotope Separation Studies Service at Saclay. Describes an electromechanical analog simulator built from CSF fire-control computer components to solve up to 35 linear differential equations representing transient isotope concentration regimes in gaseous diffusion cascades. The report covers the mathematical derivation of simulation equations via finite-difference approximation, hardware architecture (functional blocks, 5-rack layout, 472 kc/s HF integrators), accuracy assessments (2% steady-state, 2–10% transient), and practical applications including perturbation compensation, predetermined transitions, and full start-up schedule optimization for a 640-stage uranium enrichment plant.
- Die Lösung und Darstellung von partiellen Differentialgleichungen auf dem elektronischen Analogrechner
German-language article from the 1962 series 'Elektronische Datenverarbeitung — Fachberichte über programmgesteuerte Maschinen und ihre Anwendung' (Heft 5/1962) addressing the solution and display of partial differential equations on electronic analog computers. Covers the method-of-lines finite-difference discretization approach for parabolic (heat conduction) and hyperbolic (wave equation) PDEs, the Laplace transformation programming method, and oscilloscope display techniques including quasi-3D surface plots for visualizing the solution surface u(x,t). Practical circuit diagrams and worked numerical examples are included.
- Development of New Methods and Applications of Analog Computation: I - An Experimental Electronic Generalized Integrator; II - Nonstationary Noise for Monte Carlo Studies
Quarterly progress report (September–December 1961) for NASA Contract NAS8-2473, covering two research tasks at the Georgia Tech Analog Computer Laboratory. Part I describes the design and construction of an all-electronic Generalized Integrator capable of integrating analog voltage signals with respect to arbitrary variables, including circuit diagrams for threshold detectors and sampling gates. Part II analyzes techniques for generating nonstationary noise voltages for use in analog-computer Monte Carlo studies, with particular focus on nonstationary shaping of Gaussian band-limited white noise using variable and separated linear networks.
- Automatic Analog Computer Control by Means of Punched Cards — "CRESSIDA I"
NASA Technical Translation TT F-8843 of EURATOM CETIS Report No. 46 (April 1962), authored by Armand Van Wauve at the Ispra Scientific Information Data Processing Center. Describes the CRESSIDA I project, which automates static digital-analog coupling for EAI PACE 231R analog computers by linking the ADIOS console to a modified IBM 026 card punch, enabling punched-card input/output of analog quantities and automatic coefficient setting via the APACHE II language processed on an IBM 7090. The 28-page report covers system architecture, relay-based control circuits, instructions for IBM 026 operation as an ADIOS I/O unit, and future plans including CRESSIDA II.
- Analog Computer Fundamentals: With an Introduction to Matrix Programming Methods
A 1962 instructional textbook by Silvio O. Navarro, Associate Professor of Electrical Engineering and Director of the Computing Center at the University of Kentucky, covering analog computer fundamentals and matrix programming methods. The text introduces basic analog building blocks (potentiometers, operational amplifiers, adders, integrators, function generators, multipliers), techniques for solving ordinary and partial differential equations on analog computers, machine components and patching, and an advanced chapter on matrix-based programming methods for systematic problem setup. Produced under the Ford Foundation Project on the Use of Computers in Engineering Education and distributed through Wadsworth Publishing Company.
- Aufbau und Arbeitsweise des Hybrid-Rechners TRICE
A German-language technical article by W. Ameling (EA GmbH Aachen) describing the construction and operation of the TRICE hybrid computer (Transistorized Realtime Incremental Computer), a transistorized incremental digital computer developed by Packard-Bell. The article explains the basic computational units (integrators, adders, multipliers, servo, and analog-digital converters), the programming method for systems of differential equations using incremental arithmetic, and the machine's performance characteristics including operation at up to 100 kHz iteration rate. Published in Elektronische Rechenanlagen, Vol. 4, No. 1, 1962, pp. 28-44.
- The Heath Electronic Analog Computer: Its Usage for the Solution of Engineering Problems
A 1962 Master of Science thesis from Villanova University presenting a tutorial on electronic analog computation using the Heath Electronic Analog Computer, which features fifteen operational amplifiers, potentiometers, initial-condition power supplies, four relays with four transfer contacts each, and eight vacuum diodes operating in repetitive (0.6–6 cps) or non-repetitive modes. The thesis develops a systematic amplitude and time scaling methodology and demonstrates it through worked examples including second-order linear differential equations, simultaneous first-order systems, a servomechanism simulation, and a proposed frequency analyzer. Special circuits for multiplication, dead time, dead space, and hysteresis are also surveyed, and the Heath machine is assessed as an excellent educational introduction to analog methods.
- Instruction Manual for Analogue Computer SCD 10
Instruction and maintenance manual for the Solartron SCD 10 Analogue Computer, a general-purpose medium-capacity machine intended as a design tool or educational aid. Covers technical description of control panel, patch panels, and reference power supplies; installation and test procedures; and breakdown instructions with component lists. The SCD 10 features differential equation solving, servo multipliers, resolver connections, and a repetitive timer suited to problems such as servomechanism analysis and automatic control.
- Tisch-Analogrechner: Beschreibung und Bedienungsanleitung (Desktop Analog Computer: Description and Operating Manual)
Description and operating manual (MV 2 460568, dated 1 March 1961) for the BBC desktop analog computer manufactured by Brown, Boveri & Cie in Mannheim. Covers fundamental principles of electronic analog computing including operational amplifiers, summation, integration, and coefficient potentiometers, followed by operating instructions for the specific machine.
- Beschreibung und Bedienungsanleitung des Präzisions-Analogrechners RA 800
German-language description and operating manual for the Telefunken RA 800 Precision Analog Computer. Covers mechanical layout, programming field design with 10 fields of plug-in computing element modules, operating modes (summing, integrating, holding), and specifications for modulation multipliers, parabolic networks, servo multipliers, and potentiometers. The RA 800 features chopper-stabilized amplifiers with less than 0.01% error, a built-in digital voltmeter, and a removable programming field with illuminated pushbutton selection of operating modes.
- Simulation of Full and Part-Load Performance of a Free-Piston Gas Generator by Electronic Analog Methods
Master of Science thesis submitted to the United States Naval Postgraduate School (1960) by Lieutenant Commander Alan F. Barnes. The work uses an electronic analog computer (Boeing Electronic Analog Computer) to simulate the full and part-load performance of a free-piston gas generator (SIGMA GS-34), modeling piston dynamics via Newton's second law with analog circuits representing combustion, compression, bounce-cylinder, and friction forces. Results demonstrate that analog simulation can reproduce free-piston gas generator behavior with reasonable accuracy, validating the method for design and performance prediction of free-piston engine systems.
- Introduction to Electronic Analogue Computing
An experiment manual prepared by Argonne National Laboratory (ANL-6187) to introduce participants in the International Institute of Nuclear Science and Engineering to electronic analogue computing. Covers general theory of electronic analog computers (operational amplifiers, integrators, differentiators, servo multipliers, servo dividers, differential relays), operational information for the Electronics Associates PACE computer, analog programming techniques, and worked experiments including sine-wave generation, xenon buildup in a reactor, reactor kinetics, and isotopic abundance in fast reactors.
- Über die Nachbildung und Untersuchung von Abtastsystemen auf einem elektrischen Analogrechner
A 1960 journal article (reprint AH 507) by G. Schneider of the AEG Institute for Automation, Frankfurt, published in Elektronische Rechenanlagen Vol. 2, pp. 31–37. The paper presents a new method for simulating sampled-data (pulsed-data) systems on an electric analog computer, covering the construction of both sampling elements (using relays and RC circuits) and difference-equation elements (via cascaded sampling units acting as delay-line synthesizers). A detailed worked example demonstrates synthesis of optimal difference-equation compensators for finite-time settling of both reference and disturbance step responses, along with a general approach for solving arbitrary difference equations on the analog computer.
- Divide and Multiply with a Wheatstone Bridge
A two-page article from Radio-Electronics (June 1960) by Forrest H. Frantz Sr. describing how a properly configured Wheatstone bridge circuit can function as a simple analog calculator for multiplication and division. The article presents the bridge resistance relationship (A/B = C/D), construction instructions for a practical panel-mounted calculator using potentiometers and a null detector, and several worked example problems demonstrating its use.
- Instruction Manual: Model 3103 Dual DC Amplifier (Chopper-Stabilized) and Model 3732 Electronic Multiplier (Quarter-Square Type)
Two bound instruction manuals for Donner Scientific Company (a division of Systron-Donner Corporation) analog computer plug-in units. The Model 3103 (August 1960) covers the Dual DC Amplifier using chopper-stabilization, including specifications, installation, operation, circuit description, servicing, parts list, and schematic (Drawing No. 5217). The Model 3732 (July 1961) covers the Electronic Multiplier using the quarter-square technique, providing similar operator and maintenance reference material for use with Donner 3000-series analog computers.
- Instruction Manual: Model 3500 Analog Computer (Portable)
Instruction manual for the Donner Model 3500 Portable Analog Computer, manufactured by Donner Scientific Company (a division of Systron-Donner Corporation) in January 1960. Covers computer theory (including an outline for non-electronics personnel), programming and operation, circuit description, servicing, and a parts list, with appendices containing schematic diagrams, demonstration problem connections, tech notes, and a potentiometer loading chart. The 49-page manual addresses both the portable bench configuration and rack-mount installation of the Model 3500.
- Operational Manual for the Heath Educational Analog Computer Model EC-1
The operational manual for the Heathkit EC-1 Educational Analog Computer covers fundamental analog computing theory, circuit description, and step-by-step operating instructions. The EC-1 features nine DC operational amplifiers (6U8 tubes, open-loop gain ~1000, output ±60 V at 3 mA), five coefficient potentiometers, three initial-condition power supplies (0–100 V), and a multivibrator for repetitive operation at 0.1–15 cps. Illustrative problems—falling body, spring-mass system, simultaneous algebraic equations, projectile, and bouncing ball—demonstrate addition, multiplication by a constant, and integration on a machine intended for teaching and demonstration in engineering, physics, and mathematics.
- An Analog Computer Study of the Effectiveness of Interceptor Commands Derived from a Prediction Equation of Second Order
NASA Memorandum 10-7-58A from Ames Research Center presenting an analog computer study comparing first-order and second-order prediction equations for automatic interceptor guidance on lead-collision courses against maneuvering targets. The authors derive second-order prediction equations that allow the interceptor to fly a straight-line course against a target with constant acceleration, then use an analog computer to analyze system stability and evaluate rocket miss distance under various conditions including limited/unlimited interceptor acceleration, constant and pulse target maneuvers, and varying rocket speeds. Results demonstrate improved miss distance performance with second-order commands compared to first-order prediction schemes.
- Der elektronische Analogrechner und seine Verwendung in der Industrie
A 13-page lecture summary by AEG engineer W. Ammon covering the history, structure, and programming of electronic analog computers, with practical application examples including electric braking of a field-controlled DC motor, synchronous generator voltage control, nuclear reactor dynamics, and cyclotron particle trajectories. The document explains normalization and time transformation techniques for scaling differential equations to machine units. It concludes with a comparative table of analog versus digital computer characteristics, noting 1–5% solution accuracy and the analog computer's superiority for solving ordinary differential equations in real time.
- Übersicht über die Technik der elektronischen Analogrechner
Introductory technical article by E. Kettel published in Telefunken-Zeitung (Vol. 30, June 1957, Issue 116, pp. 129–145) presenting a comprehensive overview of electronic analog computer technology. Covers computing elements (summation, integration, sign inversion, multiplication, function generation), the theory and implementation of drift-free DC operational amplifiers, and a detailed treatment of the diode-network parabolic multiplier used in Telefunken's own repetitive analog computer (with 22 sum/integrate units, 8 multipliers, ±100 V machine unit). Includes measured error data showing multiplier accuracy better than 0.2% with the described correction techniques.
- Analog Computers in Process Design (Application Bulletin No. 3)
EAI Application Bulletin No. 3, authored by Charles W. Worley, demonstrates the use of PACE analog computers in the simulation and design of industrial process control systems. The bulletin covers analog circuit setups for pneumatic proportional-plus-reset controllers, heat exchangers, distillation column material balances, first-order chemical reactions, and catalytic reactors, with governing differential equations and corresponding computer patch diagrams for each. A reference table of PACE general-purpose analog computer component symbols is appended.
- Automatic Navigation Computer ASN-7
Sales brochure for the Ford Instrument Company ASN-7 Automatic Navigation Computer, a self-contained airborne dead-reckoning system that continuously displays course, distance, and present position. The ASN-7 accepts inputs of heading, true airspeed, magnetic variation, and wind speed/direction to compute and display geographic coordinates of present position and destination; it supports an alternate stored destination and Doppler radar integration. Weights, dimensions, input/output specifications, and a competitive comparison table are provided, along with descriptions of accessories under development including a Polar Heading Adapter and Automatic Fix Corrector.
- Simulation of Steam Pressurizing Tank Transients by Analog Computer
A 1956 master's thesis from the US Naval Postgraduate School presenting analog computer simulation of thermodynamic transients in a nuclear reactor steam pressurizer vessel, using a Boeing Electronic Analog Computer with a Sanborn Recorder. The authors develop theoretical equations from thermodynamic first principles and empirical steam-table relationships, then implement them on the analog computer to generate design data for pressurized water reactor pressurizer sizing at 2000 psia. Results include pressure prediction curves and design guidance for minimizing tank size while accommodating normal and accidental surges.
- Simulation of a Turbojet Engine on a Standard Electronic Analogue Computer for the Purpose of Control Study
A 1956 thesis by U.S. Navy lieutenants Rockcastle and Yates at the Naval Postgraduate School presenting a simulation of a turbojet engine on a standard electronic analogue computer for control study purposes. Non-linear equations describing the engine's static and transient behavior are derived and linearized for analogue implementation; a typical fuel control is simulated and exercised under both transient and steady-state conditions. Results demonstrate that accurate engine simulation is achievable without special-purpose equipment and that positive fuel-flow limiting can maintain maximum allowable turbine inlet temperature during acceleration.
- Analog Computer Techniques
A 1956 textbook by Capt. Clarence L. Johnson (USAF, U.S. Air Force Institute of Technology) covering the theory and practical use of electronic analog computers (differential analyzers). Topics range from linear computing components, amplitude and time scaling, and synthesis of servomechanism systems, through nonlinear and function-generating techniques, repetitive analog operation, and a concluding introduction to digital differential analyzers. The book was developed from computer courses taught to undergraduate and graduate students at Wright-Patterson Air Force Base and is pitched at readers with knowledge of Ohm's law, Kirchhoff's laws, and basic differential equations.
- Production en série d'un nouveau matériel : Les Calculateurs C.S.F.
A French-language promotional brochure from CSF (Compagnie Générale de TSF) documenting the series production of 100 analog ballistic fire-control calculators for the French Army, delivered in approximately 24 months from 1953–1955. The brochure details the integrated manufacturing chain across CSF group subsidiaries (C.I.C.E., C.A.M.E.C.A., S.T.E.L., S.F.R.) covering special ceramic capacitors, precision servo motors, tube-free calculation blocks, stabilized power supplies, and trailer-mounted cabinet assembly. Quality-control tolerances of under 2 microns for condenser components are highlighted, along with final ballistic acceptance testing and delivery of self-contained trailer units.
- EASE Computer Installation Instructions
Installation instructions for the Beckman EASE analog computer system, covering site preparation, cabinet arrangement, ground bus connections, and 115 V AC line power wiring for the Model 1187 control unit cabinet and Model 1185 operational component cabinets. The manual details d-c voltage requirements and current capacities for the Model 1001, 1010, and 1015 power supplies and provides inter-cabinet cabling procedures for the Model 1041 Operational Amplifier Unit, Model 1031 Multiplier Panel, Model 1051 Multiplier, and associated function generators and set-up units.
- Description of Ground Position Indicator Type A-1
This document describes the Ford Instrument Company Ground Position Indicator (GPI) Type A-1, a four-unit airborne system prepared for the U.S. Air Force that continuously computes and displays present latitude and longitude of an aircraft in flight. The system weighs approximately 45 pounds (exclusive of cables), operates from 115 V 400-cycle and 28 V DC power, accepts true airspeed, compass heading, wind direction, wind force, and magnetic variation inputs, and achieves a maximum total air-position error of about 1.5% of computed nautical miles traveled. The document covers operating principles, component descriptions (Preset Control Box, Computer Unit, Amplifier Unit, Ground Position Indicator panel), dimensional drawings, and the trigonometric geometry underlying the latitude/longitude integration.
- Probleme der Entwicklung programmgesteuerter Rechengeräte und Integrieranlagen
A 51-page German technical report (Aachen, 1953) compiled from seminar lectures given at the Mathematisches Institut Lehrstuhl C during the 1952 summer and 1952/53 winter semesters, edited by Prof. Dr. Hubert Cremer. The three chapters cover: (1) program-controlled computing machines including stored-program concepts, construction problems, and error correction; (2) development of the Integromat analog integration device including the individual electronic integrator, the step-rate generator (Schritttaktgeber), and error analysis; (3) optimal control problems and their mathematical formulation, together with application of the Integromat to solving such problems.
- Analog Computers: RCA Typhoon, 1951
A descriptive article covering the RCA Typhoon, built under Navy Bureau of Aeronautics contract and entering service in early 1951 as one of the largest analog computers ever made, housing approximately 4,000 vacuum tubes in 43 racks. The machine featured 450 precision DC amplifiers, 20 computing servo units with multipliers, up to 80 simultaneous integrations, and ultra-stabilized power supplies regulated to 0.001% of full scale. The article draws on Electronics magazine issues from 1951 and describes architecture, circuit details, and operational requirements of the system.
- Determination of Rate, Area, and Distribution of Impingement of Waterdrops on Various Airfoils from Trajectories Obtained on the Differential Analyzer
NACA Research Memorandum (RM No. 9A05, February 1949) in which University of California researchers use a differential analyzer to solve the differential equations of waterdrop motion around Joukowski airfoils. Trajectories are computed for three airfoil/angle-of-attack cases, yielding the rate, area, and distribution of waterdrop impingement as functions of two dimensionless moduli; results are compared with impingement data for cylinders. The work demonstrates the differential analyzer as a practical tool for aeronautical icing calculations otherwise requiring laborious numerical integration.
- Computing Mechanisms and Linkages
Volume 27 of the MIT Radiation Laboratory Series, authored by Antonin Svoboda and edited by Hubert M. James. Covers the mathematical design of mechanical computing mechanisms and linkage computers, including harmonic transformers, three-bar linkages, cams, integrators, resolvers, and bar-linkage combinations. Developed under wartime pressure for practical methods of designing linkage-based analog computers; originally published by McGraw-Hill in 1948.
- Anwendung der Braunschen Röhre für die Auflösung von Differentialgleichungen auf elektrischem Wege
A three-page German journal article (Archiv für Elektrotechnik, Vol. XXXIII, 1939) by Hans Kleinwächter describing an early analog-computing technique in which a specially constructed Braun tube (CRT) with a resistance-rod collector and inductance-coil differentiator solves ordinary differential equations electrically. The beam position encodes the dependent variable y, an inductance in the anode circuit of an auxiliary tube produces y′, and the Wehnelt-cylinder/deflection arrangement multiplies two variables; circuit schematics for first- and second-order equations are provided and the method is generalized to nth-order cases.
- GP-6 Analog Computer
Four-page product brochure for the Comdyna GP-6 Analog Computer, describing its internal components (8 operational amplifiers, summer resistor networks, inverter networks, electronic switch networks, integrator capacitor sets, 8 coefficient potentiometers, multiplier/divider boards), patch panel design using bread-boarding or PC board fabrication, and ease-of-operation features including an internal DVM digital readout, two-axis address for computed variables, manual and repetitive operation modes, and a visual overload indicator. The brochure also covers interconnections with analog/digital and microcomputer systems, performance specifications (stable roll-off, high FET input impedance, low drift), four time scales per integrator, and applications in laboratory simulation, circuit needs, classroom teaching, and control system design.
- 7000 Analog/Hybrid Computing System
Sales brochure for the Comdyna 7000 Analog/Hybrid Computing System, a modular building-block hybrid computer configurable as a general-purpose analog computer, hybrid computer, digital-computer peripheral, small processor, or large simulator. The system's centerpiece is MICROPATCH, a digital-computer-controlled patch-programming subsystem that stores, recalls, and modifies analog patch configurations under software control. The brochure also covers the GP-10 analog computing unit, the Control Unit with repeat and hold modes, and analog-to-digital conversion hardware for interfacing with external digital computers.
- 808 Analog Signal Processor
A product brochure for the Comdyna 808 Analog Signal Processor, a low-cost analog computer designed to process raw instrumentation measurement data in real time. The 808 provides eight operational amplifiers with wide frequency range, summation, integration, and coefficient multiplication, plus signal conditioning elements such as precision potentiometers and overload indication, enabling it to bridge raw instrumentation signals and digital data acquisition systems. Typical applications described include implicit measurement, data reduction, process control, and preprocessing of digital computer inputs.
- 808 Analog Signal Processor Operator's Manual
Operator's manual for the Comdyna 808 Analog Signal Processor, a standalone or peripheral analog computer unit with ten 2K coefficient potentiometers, an 11-position amp/pot address switch, a 3-position mode selector (IC/OP/Hold), and a 25-pin trunk and readout connector. The manual covers internal features, patch panel operations, trunk connector pin assignments, system schematics, assembly drawings and parts lists for the quad amplifier and power supply boards, and adjustment procedures for the Model 982 dual multiplier network and the Model 731 variable diode function generator.
- Models 701 and 709 Variable Diode Function Generators
Single-page product brochure for the Comdyna Models 701 and 709 Variable Diode Function Generators (VDFG). The Model 701 features fixed breakpoints with adjustable slopes and 11 straight-line segments for approximating arbitrary non-linear curves, priced at $165; it includes an internal inverter amplifier so segments can be positive or negative, with functions generated across all four quadrants. The Model 709 extends the capability with both adjustable breakpoints and adjustable slopes, offering 5 positive and 5 negative breakpoints each adjustable anywhere within the full 10 V range, enabling 21 or more segment curve approximations, priced at $205.
- GP-6 Analog Computer Operator's Manual
This combined Operator's and Maintenance Manual for the Comdyna GP-6 analog computer covers operating procedures, operator functions, and patch panel operations. It describes the GP-6's computing elements — summers, integrators, multipliers, dividers, squarers, square-root extractors, differentiators, and track/store units — with schematic diagrams and patch panel wiring instructions. Maintenance sections address coefficient potentiometer calibration, digital voltmeter circuitry, the 982/983 dual multiplier network, and a scaling review example.
- Banana Plug Modules: Plug-in Networks for Comdyna and EAI Analog Computers
A two-page price-list datasheet for Comdyna banana plug modules — self-contained plug-in computing networks compatible with Comdyna analog computers and EAI TR-20/48 and 380/580 analog computers. The sheet lists part numbers 9302 through 9780 covering D/A electronic switches, comparator feedback elements, function switches, coefficient potentiometers, limiters, zero limiters, dead-space networks, absolute-value circuits, two-input summer networks, and patchable diodes, each with specifications and quantity-break pricing (1-3, 4-9, and 10-15 units). Modules patch directly to standard 3/4-inch hole-spacing banana jacks and are offered on a two-week trial basis.
- GP-6 Analog Computer Operator's Manual
Complete operator's manual for the Comdyna GP-6 analog computer, covering operating procedures for slow-time and high-speed repetitive modes, readout instrument calibration, coefficient potentiometer setting, patch panel programming symbols and operations, and multi-unit slaving. Includes detailed descriptions of internal assemblies—the 911 Quad Amplifier, 116-2 Power Supply, 933/934 Time Base, 970-1 Overload Indicator, 982 Dual Multiplier Network, and 905 Digital Voltmeter—plus accessories such as the Model 709 Variable Diode Function Generator, Model 771 Transfer Function Simulator, and the 9300-series D/A Electronic Switch banana-plug modules.
- Une nouvelle technique de calcul analogique — Le calculateur électronique
A French-language article by CSF describing their AC-based analog computation technique, in which voltages represent variables and cylindrical variable capacitors with servo motors replace conventional DC potentiometers. The article explains the three fundamental algebraic operations (multiplication by a constant, addition, and function evaluation), illustrates example calculator setups for coordinate transformation, differentiation, and integration, and concludes with an extended application to anti-aircraft (DCA) fire-control, showing how CSF analog computers track aircraft, compute firing solutions, and drive gun-laying systems.
- Analogrechner DORNIER 240
Technical brochure describing the DORNIER 240, a fully transistorized precision desktop analog computer operating at a 10 V computing voltage with up to 49 computing amplifiers in full configuration. The document covers the machine's modular architecture, patch panel layout, operating modes, and computing elements including summing integrators, summers, parabola multipliers, variable diode function generators, hand potentiometers, and an optional TTL logic supplement. Key features include amplifier bandwidth exceeding 350 kHz, addressable computing elements, repetition frequencies up to 78 Hz, and interchangeability of elements with the DORNIER 720.
- Dornier-Analogrechner 240/720 Programmierfeld
A single-page color-coded patch panel reference sheet (Programmierfeld) for the Dornier Analogrechner 240/720 analog computer. The diagram illustrates the full jack matrix layout with color-distinguished rows for integrators, summing amplifiers, coefficient potentiometers, comparators, and switches, enabling the operator to record and reproduce program patch configurations. Blank 'Programm' and 'Programmierer' fields at the bottom allow hand-written identification of specific programs.
- Analogrechner Dornier 720
Product brochure for the Dornier 720, a fully transistorized precision analog computer operating at 10 V with a modular architecture supporting up to 145 amplifiers, of which 36 can serve as electronically controlled integrators. The brochure covers the display and control panel, optional logic add-on with 24 flip-flops and counters, application areas spanning control engineering, aerospace, chemistry, and education, hybrid computing integration (electronic servo-potentiometers with 10 ms setting time), and a detailed breakdown of the six-sector programming board with module-level component listings.
- Dornier DO 80 Analogrechner — Bedienungsanleitung
Operator manual for the Dornier DO 80, a compact 10-volt desktop analog computer in a 19-inch rack enclosure. Covers front-panel controls, operating modes (IC/HT/Compute, repetitive and single-shot), rear-panel I/O for parallel multi-computer coupling and external recorders, and construction and patching of integrator, summing amplifier, multiplier, and potentiometer modules with programming examples. Specifications include amplifier bandwidth >20 kHz, integrator drift 80 μV/s in Hold, and multiplier static error 1% FS.
- DO-80 Prototyp — Standardbestückung, Spezifikationen und Schaltungsunterlagen
Internal engineering dossier for the Dornier DO-80 analog computer prototype, containing the standard module configuration (8 integrators/summers, 4 summers, 4 inverters, 4 multipliers, 2 comparators, 8 potentiometers), detailed electrical specifications, hand-drawn circuit schematics for every plug-in module (integrators, summers, comparators, control unit, timer, power supplies, reference voltage), wiring harness diagrams, individual integrator control and potentiometer modules, mains connection board, and a comprehensive set of mechanical construction drawings with dimensioned front-panel and housing cutout layouts. Power supply is 220 V / 50 Hz, approximately 40 W; machine dimensions 443 × 237 × 277 mm; amplifiers are BB 3307/12C and BB 3308/12C op-amps with ±15 V rails and ±10 V reference; compute time adjustable from 0.1 s to 110 s.
- Simulationssystem DO 910 — Bedienungshandbuch
Operator's manual for the Dornier-System GmbH DO 910 hybrid simulation system, which couples a Commodore CBM 8032 computer (32 KB BASIC) to a 25-slot analog section derived from the DO 80 analog computer, interconnected via an IEC 625 (IEEE 488) interface. The manual covers system architecture, MONITOR software operation, patch-field connections and programming examples for all module types (integrators, summers, multipliers, comparators, limiters, function generators, logic, and dead-time element), and an appendix providing complete BASIC code for IEC read/write transfers to the interface.
- Simulationssystem Dornier 960 — Do 960 Systembeschreibung
A German-language promotional brochure and system description for the Dornier 960 (Do 960) hybrid simulation system, covering its CAMAC-based bus architecture, Intel 8080 microprocessor control, and modular analog computing elements. The Do 960 accommodates up to 16 plug-in modules on the Do 960 Bus, each containing integrators, summers, multipliers, digital potentiometers, function generators, limiters, comparators, and electronic switches. Detailed patch-field diagrams and specifications are provided for each computing element type, along with a description of the MONITOR software, BASIC interpreter, and optional logic extension module.
- Let Us Demonstrate How the Du Pont 310 Curve Resolver Reduces Complex Curves to Component Peaks Quickly and Inexpensively
A one-page advertisement from Du Pont Instruments promoting the 310 Curve Resolver, a compact analog instrument that decomposes complex overlapping curves (from chromatography, electrophoresis, NMR spectroscopy, X-ray diffraction, and similar techniques) into individual component peaks. The operator works directly with the instrument's up to ten function generators to match synthetic peak shapes to the original curve on an oscilloscope screen, with the algebraic sum displayed simultaneously. An optional X-Y plotter and integrator are mentioned for recording and area measurement.
- EAI-1000 Diagnostic Routines (Section 8.11–8.13 and Diagnostic Box Reference)
This document is an extracted section (pages 8.25 onward) from the EAI-1000 reference manual covering the use of the diagnostic box and diagnostic software routines for troubleshooting the EAI-1000 hybrid analog computer. It describes the diagnostic box hardware — a 40-way flat-cable peripheral that replaces the HCI microprocessor card to isolate faults — and provides a numbered test matrix covering data bus/RAM storage, keyboard reading, device selection for the analog bus, A/D conversion, and the display panel. Each test entry specifies the switch settings ([AB], [CD], [EF]), the pass/fail criteria observable via oscilloscope or the indicator register, and details on chip-level failure modes (IC42, IC38, IC35, RAM chips 8111/8085/8212, EPROMs, and TTL buffers).
- Das EAI 180 Analog/Hybrid-Rechensystem
German-language product brochure for the EAI-180 analog/hybrid computer, a compact desktop-class machine intended for education and research. The brochure details the system's analog section (12 summers/integrators, 8 potentiometers, multiplier, diode function generators) and logic section (AND/NAND gates, flip-flops, BCD and binary counters), along with key specifications including 10 V reference voltage, 100 kHz amplifier bandwidth, and ±0.25% component precision. Applications, available output peripherals, and the broader EAI product lineup are also described.
- EAI 580 Computing System — General Maintenance Instructions (Chapter 2)
Chapter 2 of the EAI 580 Computing System maintenance documentation, covering general maintenance instructions. The chapter details preventive maintenance schedules (daily/weekly and semi-annual checks covering power supplies, amplifiers, multipliers, function generators, DVM calibration, and potentiometer accuracy), printed-circuit board soldering and component replacement techniques, transistor and diode servicing procedures including heat-sink mounting with silicone grease, and general system troubleshooting guidance using dynamic testing, oscilloscope display, and plug-in tray substitution. Maintenance equipment recommendations specific to the EAI 580 are also provided.
- EAI 580 Console Manual — Chapter 6: Overload Indicators
Chapter 6 of the EAI 580 analog computer console manual, covering the visual overload indicator subsystem. The chapter explains the theory of operation for amplifier overload detection circuits (including NRPD and audio overload circuits), provides maintenance and troubleshooting procedures for the overload panel, and includes a replaceable parts list with tables for the control tray, control cards 1 and 2, and visual overload alarm assemblies (models 0.20.1018-2 and 0.20.1018-3). An appendix of engineering drawings provides schematics for the control tray wiring, control card circuits, the visual overload alarm assemblies, and the indicator panel layout.
- EAI 580/680 Scientific Computing System Maintenance Series: Digital Voltmeter — Chapters 4–5 (Maintenance and Calibration)
Chapters 4 and 5 of the EAI 580/680 Maintenance Series manual for the Model 28.268 Digital Voltmeter (DVM). Chapter 4 covers maintenance procedures including test connector pinout, reference circuit and power supply checks, input amplifier balance verification, resistor matrix and comparator checkout, digitizing circuit troubleshooting, accuracy checks with tabulated input/readout tolerances, and display unit lamp replacement and lens adjustment. Chapter 5 provides the full calibration procedure, specifying required test equipment (precision voltage divider, galvanometer, stable DC source), reference level adjustment using the 6.750 Reference Amplifier, full-scale adjustment, and summing resistor trim pot procedures for the ±100 V, ±10 V, ±1 V, and ±0.1 V ranges.
- Appendix 2: Drawings — Digital Voltmeter, Model 26.268
This document is Appendix 2 of the EAI Digital Voltmeter Model 26.268 manual, containing the complete set of engineering schematics and wiring diagrams for that instrument. It covers the top-level 26.268 DVM schematic (4 sheets) and wiring (5 sheets), plus individual drawings for all major subassemblies: the 6.463-6 Dual DC Amplifier, 6.736-1 Reference Amplifier, 12.937-5 Miscellaneous Network, 12.1106 Rectifier Network, 12.1654 Conversion Delay Network, 26.116-1 Summing Resistor Network, 26.240 Comparator Amplifier, 26.242 Comparator and Diode Gate Network, 38.032/38.032-1 BCD Counter and Decimal Decoding Matrix, 43.141 Power Supply Regulator, and 44.302-1 Programmer. All drawings are prepared by Electronic Associates, Inc. of Long Branch, New Jersey, in accordance with government electromechanical drafting standards.
- Appendix 3: Model 26,285-1 Digital Voltmeter
Appendix 3 from the EAI 580 Digital Voltmeter manual series, covering the Model 26,285-1 Digital Voltmeter — a variant identical to the Model 26,260-0 except for the addition of two buffer inverter circuit cards. The appendix provides an introduction and specifications (including output connector J3 pin/function assignments for BCD ranges from units to 1000s), a parts list and drawings index for the DVM and the 6,657-0 Buffer Inverter, interior photographs identifying major assemblies, and a full set of schematics and wiring diagrams for both units.
- EAI MiniAC Reference Handbook
The EAI MiniAC Reference Handbook is a 224-page operator reference for the Electronic Associates, Inc. MiniAC hybrid analog computer. The handbook covers the machine's computing components — including integrators, summers, track-store units, multipliers/dividers, function generators, potentiometers, comparators, and a digital logic section with AND-gates, J-K flip-flops, counter/timer, and monoflop — along with patchboard programming procedures and operating modes (IC, OP, HD, PP, SP, SL). It serves as the primary programming and operation reference for laboratory or classroom use of the MiniAC.
- Hilfsblätter zum Praktikum Analogrechner (Mini-AC)
A German-language laboratory reference handbook produced by RWTH Aachen (Rheinisch-Westfälische Technische Hochschule Aachen) for use with the EAI Mini-AC hybrid analog computer. The 40-page document covers the patchboard layout, component inventory (6 integrators, 3 summers, 3 track-store units, 3 multipliers/dividers, 2 function generators, 18 potentiometers, 3 comparators, and a full digital logic section with 10 AND-gates, 4 J-K flip-flops, counter/timer, and monoflop), and detailed operating principles for all analog, digital-analog, and digital element types including the IC/OP/HD/PP/SP/SL operating modes and repetitive computation timing.
- Analog Computer Application Bulletin No. AB-856: Process Control Problems Yield to the Analog Computer
EAI Application Bulletin No. AB-856, reprinted from Control Engineering, demonstrates how an analog computer can simulate a batch chemical process and its cascade control system to determine optimum controller settings and valve configurations. The bulletin covers mathematical modeling of the kettle, water jacket, and steam/cooling systems using integrators, multipliers, and potentiometers, with example simulation runs comparing single-loop and cascade control strategies. Results show that the cascade system substantially outperforms single-loop control in rejecting disturbances such as sudden steam-pressure changes.
- Series 3440 DATAPLOTTER
Product brochure for the EAI Series 3440 DATAPLOTTER, a fast and accurate automatic digital plotting system capable of point, line, and symbol plotting from magnetic tape, punched tape, punched cards, manual keyboard, or analog signals. The system incorporates a built-in VARIPLOTTER (EAI Model 205) for digital-to-analog conversion and accommodates plots up to 20x20 inches. Specifications include accuracy within 0.001 inches, plotting speeds up to 500 lpm for line plots from magnetic tape and up to 300 ppm for punched cards, and a 13-command control code set for fully automatic operation.
- Two Variable Function Generator Program for HYDAC
This two-page EAI bulletin (No. ALHC 64020) describes the F(x,y) HYDAC program, a hybrid-computer software routine that generates arbitrary functions of one or two variables using components of the EAI Digital Operations Systems (DOS). The program represents a function of one variable as 15 straight-line segments connecting 16 evenly spaced breakpoints, and extends this to two variables by defining multiple such curves at breakpoints in the second variable, with linear interpolation applied in both dimensions. Input is loaded from punched paper tape, enabling rapid setup; unused DOS components remain available for additional logic and computing tasks.
- HYDAC Hybrid Digital-Analog Computer Series 2000
A promotional brochure for the EAI HYDAC (Hybrid Digital-Analog Computer) Series 2000, a general-purpose computing system combining analog and digital operations in twin control consoles. The system incorporates proven PACE 231R analog computing components alongside modular digital building blocks providing logic, memory, arithmetic, and conversion functions; five major groups of digital components are available including programmed digital logic, analog memory, digital-to-analog and analog-to-digital conversion, and advanced digital arithmetic units. The brochure highlights application areas including partial differential equations, optimization, simulation of logic functions, and high-speed hybrid computation.
- MICROSTORE Model 2.395 — Product Information Release (PIR 6219)
A six-page Product Information Release (PIR 6219) from Electronic Associates, Inc. describing the MICROSTORE Model 2.395, a completely integrated solid-state accessory for the PACE 231R Analog Computing System. The unit provides high-speed tracking, storage, and switching of analog data points using solid-state electronic gates with a total switching time under 5 microseconds, and supports real-time and repetitive operation modes determined entirely by patching. Specifications include ±10 V outputs, up to 10 track-and-hold gate inputs, 200 V/µs slew capability, and a control comparator with 10 mV differential sensitivity; the release also surveys general applications such as curve fitting, boundary value problems, optimization, and stagewise simulations.
- EAI Products and Services
A 12-page product and services brochure from Electronic Associates, Inc. (EAI) covering the company's full line of analog, digital, and hybrid computing systems, including the EAI 8400 digital computer, EAI 8800 and EAI 680 analog computers, EAI 8900 and EAI 690 hybrid systems, desk-top units (TR-20, TR-48, EAI 580), and the EAI 380 modular analog/hybrid system. Additional products described include variplotters (Series 205, 95-361, 1110-1140), EAI dataplotters, reed-relay scanners (Series 6800), digital measuring systems (Series 6200), digital voltmeters (Series 6000), and application systems such as the EAI PACE II chromatographic laboratory system and an EAI cement control computer. The brochure was held by the Rechenzentrum Universitat Kiel.
- Standard Data Processing Instruments
A product brochure from EAI (Electronic Associates, Inc., Long Branch, New Jersey) presenting the firm's family of standard data processing instruments for use with analog computers. Covered products include the 1100E VARIPLOTTER (11x17-inch X-Y analog plotter with plug-in network capability and a range of accessories including function generators, time-base generator, keyboard dataplotter, and symbol printer), the 3100 DATAPLOTTER System (11x17-inch digital plotter accepting punched cards, paper tape, or keyboard input, with transistorized conversion circuits), the Series 5000 Transistorized Digital Voltmeter (full-time 1000-megohm input impedance, 0.01% +/- 1 digit accuracy, 200 readings per second), an AC-DC converter, and a high-speed printer for digital voltmeter output.
- Specifications for Transistorized General-Purpose Analog Computer
This 11-page EAI bulletin (No. PS62008-1) is a formal procurement specification for a transistorized general-purpose analog computer intended for desktop use. It covers detailed technical requirements for all major subsystems including up to 48 operational amplifiers, 40 integrator channels, 60 potentiometers, quarter-square multipliers, variable diode function generators, X2 and log-X diode function generators, comparators, function switches, pre-patch panel, reference supply, repetitive operation capability, and patching kits. Key accuracy and performance requirements are specified throughout, such as 0.01% amplifier accuracy, 350 kHz bandwidth, 20 ms to 500 ms solution time range, and plus-or-minus 10 volt reference supplies at 250 milliamperes.
- That New Idea from EAI
A four-page EAI promotional brochure advertising new analog computer developments, digital data reduction equipment, and analog plotters and recorders. Featured products include the new 221A Analog Computer, Model 2301 Electronic Digital Voltmeter, Automatic Digital Input-Output System (ADIOS), Quad Amplifier Package, Magnetic Tape Dataplotter, Transistorized Variplotter, and Portable DVM. The back page highlights EAI Computation Centers in Princeton, Los Angeles, and Europe, and describes custom engineering services in control instrumentation, system analysis, and development engineering.
- EAI Announces STARLIGHT System
A single-page EAI internal company newsletter article announcing the STARLIGHT simulation system, EAI's newest and fastest analog/hybrid simulation computer. The article describes STARLIGHT as approximately seven times faster than the runner-up CRAY machine, occupying about 55 square feet of floor space, fitting in a two-drawer file cabinet form factor, and priced at approximately $150,000. The piece also notes an ongoing NASA study contract to prove the concept by building a hardware prototype and running benchmark applications.
- Starlight: The Ultimate Simulation Computer
Four-page color sales brochure for the EAI Starlight, described as a fast real-time simulation computer using a VME-bus multiprocessor architecture with Arithmetic Computing Modules (ACMs), Data Memory Modules (DMMs), and an Analog Interface Module (AIM) providing 16 ADCs and 16 DACs. The system is programmed in CSSL, FORTRAN, C, or Ada via an Integrated Sequential Processor that compiles and maps simulation models onto the parallel ACMs at run time. A benchmark chart compares Starlight favorably to Motorola, Encore, Intel, and Cray systems in frames-per-second for dynamic simulation.
- Specifications for General Purpose Desk-Top Analog Computer (TR-10)
A formal procurement/design specification document (document number GPAC-TR-10 PS 6305) issued by Electronic Associates, Inc. for the TR-10 general-purpose desk-top analog computer. It defines detailed performance and construction requirements for all computing components: up to 20 uncommitted operational amplifiers (+-20 uV offset, 50 uV/s drift limit, 200 kHz bandwidth), up to 24 ten-turn potentiometers (0.025% resolution), up to 9 quarter-square multipliers (+-0.4% static error), X2 diode function generators, comparator, function switches, reference supplies, power supply, and a full patching element suite including a high-speed repetitive operation system cycling up to 33 solutions per second. The complete expanded system is constrained to no more than 100 lb and 16 in W x 23 in H x 16 in D.
- PACE TR-10 Analog Computer
A 16-page promotional brochure for the EAI PACE TR-10 desk-top analog computer, a fully solid-state, plug-in-component machine consuming under 60 watts and operating from 115 V/60 Hz. The brochure describes the TR-10 system architecture (attenuator, non-linear, and amplifier rows; human-engineered control panel with null meter), lists interchangeable plug-in modules (dual op-amps, integrator networks, multipliers, variable DFGs, log DFGs, comparators, function switches, reference panel, tie-point panels), works two application examples (second-order linear ODE and Van der Pol non-linear ODE), and catalogs accessories including the Accessory Group Type 2.246 for high-speed repetitive operation. Physical specifications are given: 16 in. wide x 22 in. high x 24 in. deep, 50 lb basic / fully expanded weight, power under 50 watts. Bulletin No. 60-309, published by Electronic Associates, Inc., Long Branch, New Jersey.
- PACE TR-48 Analog Computer
Marketing brochure (Bulletin No. AC 6222-1-B) for the EAI PACE TR-48 solid-state analog computer, describing its five-step problem-solving workflow, modular removable patch panel, and plug-in computing components including dual amplifiers, integrator networks, coefficient potentiometers, multipliers, variable/log/X² diode function generators, and comparators. The TR-48 is offered in four configurations (TR-48-0 through TR-48-3) scaling from 10 to 48 operational amplifiers; the fully expanded unit draws under 150 watts, weighs 320 lbs, and supports optional High Speed Repetitive Operation with solution times of 20–500 milliseconds.
- Forty-Five Pounds of Automatic Navigation
Reprinted from Sperryscope, the quarterly publication of Sperry Rand Corporation, this article describes the AN/ASN-6 Computer Set, Latitude and Longitude — a 45-pound, approximately one-cubic-foot dead-reckoning navigation computer designed and manufactured by Ford Instrument Company (Division of Sperry Rand) for USAF aircraft. The system continuously computes and displays the aircraft's present latitude and longitude by integrating true airspeed, wind speed, wind direction, and heading inputs, and also calculates course and distance to a destination. A supplementary section covers the AN/ASN-7, a follow-on airborne navigation system derived from the ASN-6 that additionally displays rhumb-line course and distance to destination.
- Bedienungsanleitung: Analogrechner EA-22
Operator manual for the GTE transistor-based analog computer EA-22, covering all operating modes (Anfangswert, Rechnen, Halten, Pot), the precision timer ZG-22 with repetitive/iterative/halt computation modes, parallel connection of multiple EA-22 units, and detailed descriptions of each operational unit: integrator-summator (ZG-A/S), double-multiplier summator (PM1-A/B), function-generator double-summator (FG-A/B with 20 diode segments), and double comparator-summator (KE-A/B). Includes procedures for zero-point adjustment, potentiometer setting, selector switch AS-22, and amplifier magazine maintenance.
- Beschreibung und Bedienungsanleitung für den transistorisierten Tischanalogrechner EA 22
Operator manual for the GTE EA 22 transistorized desktop analog computer, covering the machine's constructive design, front- and rear-panel layout, color-coded patch jack assignments, and step-by-step operating procedures. The EA 22 accommodates up to 22 computing amplifiers, 20 coefficient potentiometers, and 10 double-network operational units (integrators, multipliers, function generators) with accuracy classes down to 0.01%. Procedures cover amplifier nulling, potentiometer setting via compensation device or digital voltmeter, function generator adjustment, iterative computing with the precision time base, and memory integrator relay states.
- Technische Information Nr. 2209: Transistor-Rechenverstärker TRV-1
GTE Technische Elektronik technical information bulletin (Nr. 2209) covering the TRV-1 transistor computing amplifier, a chopper-stabilized DC operational amplifier designed for precision analog computing and measurement. The TRV-1 achieves 115 dB DC gain in the main amplifier, long-term drift ≤20 μV and temperature drift ≤1 μV/°C, implemented on a 155×105 mm printed circuit card for rack (magazine) mounting. Note: pages 1–18 of this 20-page scan are rendered unreadable by severe horizontal scan artifacts; content is derived from the two legible pages (cover and data sheet).
- Bedienungsanleitung: Schul-Analogrechner Modell EC-1-E
German-language operating manual for the Heathkit EC-1-E Schul-Analogrechner (educational analog computer), a 9-amplifier machine powered from 220 V mains with adjustable repetition frequency (1–60 Hz), 100 V reference voltage, and three initial-condition voltages. The manual covers operational-amplifier theory (summation, integration, diode nonlinearities), the balancing and setup procedure, and step-by-step programming examples including first- and second-order differential equations, spring-mass systems, polynomial simulation, PID controllers, and the bouncing-ball problem.
- Schematic: Educational Computer Model EC-1
Full circuit schematic for the Heathkit EC-1 Educational Analog Computer, labeled as page 38 of the assembly/instruction manual. The diagram covers two vacuum-tube operational amplifiers, a repetitive oscillator, coefficient potentiometers, meter junction circuitry, relay binding posts, and the complete AC power supply with transformer and rectifier stages.
- Hitachi 200D Series Analog/Hybrid Computer
Sales brochure for the Hitachi 200D Series desk-top analog/hybrid computers, covering three models: the 220D (24 amplifiers), 240D (40 amplifiers), and 260D (60 amplifiers). The series features high-speed parallel logic elements (flip-flops, comparators, counters), a 9-inch rectangular CRT display with four-channel simultaneous waveform readout and electronic marker generator, servo-set potentiometers adjustable by external signals for hybrid use, and a modular unit system allowing optional composition scaling. Key component types include dual integrators, dual multipliers, function generators, time delay units, quad electronic comparator/switch, and DA-143 DC amplifiers with overload recovery within 50 microseconds.
- Hitachi 200D Series Analog/Hybrid Computer Specification
Detailed specifications sheet covering the Hitachi 200D series analog/hybrid computers — models BA-220, BA-240, and BA-260 basic analog consoles — along with a comprehensive catalog of computing components including DC amplifiers (DA-141, DA-143), integrator networks (IN-141, IN-143), multiplier networks (EM-141, EM-143), diode function generators (FG series), potentiometers, digital logic modules (comparators, flip-flops, counters, relays), patch panels, and accessory/display devices. Key reference voltages are ±10 V; amplifiers provide 1 MHz bandwidth and open-loop DC gain of 2×10^7 typical; integrator drift is ±100 µV/sec typical. The document is distributed by Hitachi Electronics and Nissei Sangyo Co., Ltd., Tokyo.
- Hitachi Analog Hybrid Computer HITACHI-200X
Sales brochure for the Hitachi-200X analog hybrid computer, describing a desk-top or rack-mounted machine designed so that the operator patches a block diagram directly on the patch board without requiring knowledge of electronic circuit terms. The brochure covers key innovations including direct block-diagram programming, three ranges of coefficient potentiometers (0.1, 1, 10), a Program Check System (PCS), dual-point shielded patch contacts, IC-based operational amplifiers, and digital coefficient amplifiers for hybrid operation. General and individual specifications are tabulated, application examples spanning linear and nonlinear differential equations, epidemiology, germs-in-water problems, earthquake response, and industrial simulation are illustrated, and a full composition table lists available computing element configurations (A-10, A-20, 2S, 2LS, 3, 3S, 4, 4S, 4LS).
- Block Diagram of Quad DC Amplifier (Hitachi 210/240 Maintenance Manual Excerpt)
A single-page excerpt from the Hitachi 210/240 Maintenance Manual presenting Fig. 5.1.1, a block diagram of the Quad DC Amplifier. The diagram illustrates the major functional sections: Input Protective Circuit, DC Amp Portion (with output current limiter), Chopper Portion, Chopper Amplifier Portion, Chopper Portion Filter, and SI Detector (D Signal). This chopper-stabilized amplifier architecture is typical of precision analog computing elements used in the Hitachi 210/240 system.
- Hitachi 505 Analog Computer
Eight-page sales brochure for the Hitachi 505, an all-transistorized ±100 V desk-top analog computer with built-in digital logic elements for hybrid operation. The brochure covers special features including FET chopper amplifiers, electronic mode-control integrators, a shielded color-coded patchboard, a 4-digit DVM or 3-channel 9-inch oscilloscope readout, a 3-channel timer, and a 2-variable function generator. Physical and electrical specifications are given: console dimensions approximately 32 × 33 × 22 inches, weight around 300 lbs, power 115 V AC 50/60 Hz 500 VA.
- Hitachi Analog Computer 505 Operation Manual
The complete operator's manual for the Hitachi Analog Computer 505, a solid-state modular analog computer manufactured by Hitachi, Ltd. The manual covers all operating procedures including pre-patch panel insertion and removal, amplifier balance, monitoring and control systems (output selector SL-25A, digital voltmeter DV-25L, mode control), potentiometers, operational amplifiers (DA-151), quarter-square multipliers (EM-151), six types of function generators, comparators, free diodes, transfer delay elements, automatic operator, mode control panel, timers, and repetitive operation. The computer operates on a ±100 V reference and supports multiple computing consoles in a master-slave configuration.
- Hitachi 505E Analog/Hybrid Computer
Sales brochure for the Hitachi 505E analog/hybrid computer, a desk-top all-solid-state machine expandable from 10 to 124 operational amplifiers across four standard configurations (505-10, 505-30, 505-60, 505-120). The brochure details outstanding features including 100V operational amplifiers, three-cycle high-speed repetitive operation, color-coded shielded patch panel, servo-set potentiometers, built-in four-channel oscilloscope, and an integrated digital logic package with flip-flops, AND gates, counters, comparators, and mode-matrix for full hybrid computation. Component descriptions cover dual and quad amplifiers (DA-151A, DA-153), RMC and EMC integrator networks, electronic multipliers (EM-151, EM-153), variable and fixed diode function generators, relay comparators, time delay units, and a trunk unit for external digital computer interfacing.
- Le Calculateur Analogique Universel "DJINN"
Three-page French sales brochure for the DJINN universal analog computer manufactured by Laboratoires R. Derveaux of Boulogne-sur-Seine. The brochure promotes the machine to engineering design offices across fields including aviation, ballistics, electronics, and atomic energy, emphasizing its modular and demountable construction, interchangeable elements, patching board with visual block-diagram display, and low operating cost. Amplifier specifications given include an open-loop gain of 500,000, 1 W output (plus or minus 100 V into 10 kilohms), automatic zero return, input-referred drift below 0.3 mV, and input grid current below 10 to the -11 A.
- Simulateur de Pile Atomique "DJINN" — Product Brochure
Bilingual (French/English) product brochure from Laboratoires René Derveaux (France) for the 'DJINN' Atomic Pile Simulator, a 30-amplifier analog computer (Type 30 A.S.P.) designed for neutronics, kinetics, and nuclear reactor control studies with 0.5% dynamic accuracy. Also covers associated instruments including a digital gammascope, portable ionization chambers, D.C. electrometric amplifiers (C.E.A. patent), precision laboratory power supplies, and subminiature electronic amplifiers for radiation measurement applications.
- Functions
A three-page introductory mathematics handout covering the concept of real-valued functions and their relevance to mathematical modeling. Topics include the real number system (natural numbers, integers, rationals, irrationals), the definition of a function (domain and range), and four representations of functions: verbal, algebraic/symbolic, numerical table, and graphical. The document concludes with the Vertical Line Test as a method for identifying valid function graphs.
- The Sine and Cosine Functions
A calculus lecture note covering the graphs, properties, and derivatives of the sine and cosine functions, including periodicity, boundedness, amplitude, phase shifts, and evenness/oddness. The document derives that d/dx(sin x) = cos x and d/dx(cos x) = -sin x through graphical analysis of slopes and inflection points. Generalized forms A sin(kx) and A cos(kx) are examined, with formulas for amplitude |A| and period 2π/k, along with their derivatives.
- Products and Powers
A three-page calculus lecture note covering two fundamental rules of differentiation. The first section derives and applies the power rule for composite functions, showing how d/dx[(f(x))^n] = n(f(x))^(n-1) * f'(x), with worked examples including trigonometric polynomials. The second section introduces the product rule (Leibniz rule), h'(x) = f'(x)g(x) + f(x)g'(x), demonstrating its necessity and consistency with the power rule through multiple examples including verification that the derivative of a constant is zero.
- Stretches and Shifts
A three-page lecture note covering the transformation of functions by vertical and horizontal stretching (scaling) and vertical and horizontal shifting. The document defines each transformation algebraically, illustrates the effects on sine and polynomial examples, and derives the corresponding differentiation rules (constant multiple rule for vertical stretches, chain-rule precursor for horizontal stretches, sum rule for vertical shifts, and substitution rule for horizontal shifts).
- General Composition of Functions
A three-page mathematics lecture note introducing the concept of function composition, defining g∘f as the combined action of applying f then g to a real-valued input. The document covers composition notation and examples using polynomial, trigonometric, and power functions, then reframes stretches and shifts of functions as special cases of composition. It concludes with techniques for decomposing complex functions into simpler compositions, motivating the chain rule for differentiation.
- The Chain Rule
A two-page lecture note presenting the Chain Rule for differentiating composite functions. It states the rule formally, works through multiple examples including polynomial, trigonometric, and nested compositions, and demonstrates a step-by-step decomposition method. The document also illustrates applying the Chain Rule using tabular function values rather than closed-form expressions.
- Exponential Functions
A three-page lecture handout reviewing the rules of exponentiation and logarithms before introducing the exponential function f(x) = e^x and the generalized exponential function f(x) = a^x. The document covers graphical properties such as vertical intercepts, horizontal asymptotes, and the behavior of exponential functions for a > 1 and 0 < a < 1, with numerical tables and limit notation. Relevant as mathematical background for analog computer programming involving exponential and logarithmic signal relationships.
- Negative Power Functions and Their Graphs
A four-page instructional chapter covering functions of the form f(x) = x^{-n} where n is a natural number. The text addresses domain restrictions, symmetry (odd vs. even functions), horizontal and vertical asymptotes, and the differentiation rule for negative integer exponents, extending the power rule to all integers k. Worked examples include applying the Chain Rule to compositions involving negative power functions such as 1/(x+2) and (sin x)^{-3}.
- Tangent, Cotangent, Secant, and Cosecant
A four-page calculus lecture note deriving the quotient rule and applying it to define and differentiate the four remaining trigonometric functions: tangent, cotangent, secant, and cosecant. Each function's domain, range, period, symmetry, and vertical asymptotes are detailed, and worked examples demonstrate use of the quotient rule and chain rule to differentiate composite trigonometric expressions.
- Piecewise Continuous Functions
A three-page calculus lecture note covering left and right limits, the formal definition of continuity, and piecewise continuous functions. The text defines left/right limits and vertical asymptotes, distinguishes continuous from discontinuous functions, and introduces left/right continuity with worked examples. Piecewise continuous functions are presented as functions continuous everywhere except at a finite number of points, with the observation that differentiability requires continuity.
- Rational Polynomial Functions
A five-page lecture note covering rational polynomial functions and their domains, the technique of polynomial long division for decomposing such functions into a polynomial part and a remainder, and the resulting analysis of horizontal, slant, and vertical asymptotes. Three worked examples illustrate how the polynomial part governs behavior as x approaches positive or negative infinity, while the remainder governs behavior near points outside the domain. The treatment is introductory calculus-course level with no connection to analog computing hardware.
- Constant and Linear Functions
A three-page lecture note introducing constant functions f(x) = c and linear functions f(x) = mx + b, with graphical interpretation of parameters. The document covers how changing the slope m and y-intercept b affect the graph, and derives the formula for slope from two known function values, worked through with numerical examples.
- Differentiability
A four-page lecture note introducing the concept of differentiability for real-valued functions. The text develops the difference quotient and its limit as the formal definition of the derivative, works through examples for constant, linear, and exponential functions, and explains points of non-differentiability including corners and domain endpoints on closed intervals. The relationship between differentiability and locating maxima and minima — requiring inspection of both critical points and non-differentiable points — is discussed with worked examples.
- Logarithmic Functions and Their Properties
A four-page calculus course handout covering the definition and properties of logarithmic functions of the form f(x) = log_a(x), including domain, asymptotes, and intercept behavior. It derives the differentiation formula d/dx(log_a x) = 1/((ln a)x) and applies the Chain Rule to composite expressions such as ln(x^2), ln(sin x), and ln|x|. The treatment is introductory and pedagogical, aimed at a first-year calculus audience with no specific analog-computer machine context.
- General Power Functions
A lecture note covering the definition and differentiation of general power functions of the form f(x) = x^a for any real number a. The document establishes the identity x^a = e^(a ln x) for positive x, then systematically defines the function for x = 0 and negative x according to the rational or irrational nature of the exponent. The derivative formula d/dx(x^a) = ax^(a-1) is derived with analysis of where the derivative exists, illustrated by several Chain Rule examples.
- Implicit Functions
A five-page calculus lecture note covering the definition and properties of implicit functions, with worked examples drawn from conic sections (ellipses, parabolas, hyperbolas). The note develops the technique of implicit differentiation — treating y as a function of x, differentiating both sides of a relation, and solving for y′ — and identifies 'bad points' where the derivative formula is undefined, corresponding to vertical tangents.
- Quadratic Functions
A three-page instructional text covering the definition and properties of quadratic functions of the form f(x) = ax² + bx + c, including roots via the quadratic formula, discriminant analysis, and graphical behavior of parabolas (axis of symmetry, minima, maxima). The document concludes with an introduction to tangent lines and the derivative of a quadratic function, presenting the formula df/dx(p) = 2ap + b with worked examples.
- The Notion of a Derivative and Cubic Functions
A two-page lecture handout covering the general definition of the derivative as the limit of a difference quotient, with graphical illustration of secant-line approximations to the tangent. It then introduces cubic functions f(x) = ax³ + bx² + cx + d, describes the three basic graph forms, and derives the formula df/dx(p) = 3ap² + 2bp + c, working through examples with g(x) = x³ + 3x and h(x) = x³ − 3x.
- Positive Power Functions
A three-page lecture note covering positive power functions of the form f(x) = x^n for natural numbers n, including graphical properties, symmetry (even and odd functions), and derivative rules. The document derives the power rule df/dx = n·p^(n-1) and introduces the concept of higher derivatives (second, third, and ith derivatives). General mathematics educational content with no specific connection to analog computing hardware.
- Graphing Derivatives
A two-page lecture note explaining how to sketch the graph of a derivative function from the graph of the original function. The document covers constant, linear, quadratic, and cubic examples, introducing critical points, inflection points, and concavity as graphical analysis tools. A three-step procedure is presented for constructing a derivative sketch from any smooth function graph.
- Polynomial Functions
A three-page mathematics lecture note introducing differentiation rules — the sum rule, difference rule, and constant multiple rule — and applying them to polynomial functions. The document demonstrates how these three rules combine to enable differentiation of any polynomial of the form f(x) = a_n x^n + ... + a_0, with multiple worked examples including higher-degree polynomials up to degree 17. No analog computer content is present; the material is general undergraduate calculus.
- The First and Second Derivatives
A three-page calculus lecture note explaining the geometric and analytical meaning of the first and second derivatives of a function. Topics covered include increasing/decreasing behavior, concavity, the second derivative test for classifying critical points as local maxima or minima, and inflection points. The exposition uses polynomial examples to illustrate each concept.
- Sine and Cosine
A 3-page lecture note introducing the sine and cosine functions for a mathematics course. Covers the definition of radians, the extension of sine and cosine beyond acute angles via the unit circle, a table of values for common angles, and the Pythagorean identity sin²θ + cos²θ = 1.
- Transistorisierter Differentialanalysator MEDA 42 TA — Technische Beschreibung und Bedienungsanleitung
Technical description and operating instructions for the MEDA 42 TA transistorized differential analyzer, a laboratory-grade analog computer for solving systems of ordinary differential equations. Covers machine structure, power supply modules (±14 V, ±6 V, ±24 V, ±290 V rails), computing elements (10 integrators, 8 summers, 30 coefficient potentiometers, 1 quadratic function generator, 1 nonlinear function generator with 30 breakpoints, comparator), control panel operation, and operating modes (Prepare, Compute, Step, Read, Continuous). Includes schematics of power supply distribution and control plate circuitry.
- Einstellgerät für polarisierte Relais ON 280 34
Operator manual for the MEDA ON 280 34 adjustment instrument used to set and verify polarized relays (type A 4g/03/XX/V) in the MEDA-T differential analyzer series. Covers technical description, specifications (220 V, 225×250×150 mm, 3.26 kg), step-by-step relay adjustment procedure measuring contact symmetry and overdrive time (Überfallzeit), and a parts list. Oscilloscope connection is supported for visual waveform verification of relay contact dynamics.
- Two Reasons Why a Controls Laboratory Needs an Analog Computer
A two-page trade article by R.H. Spiess of Comdyna, Inc. (Barrington, IL) arguing for the use of analog computers in controls laboratories. Covers two roles: the operational amplifier as a functional circuit element for teaching transfer functions, frequency response, and compensation design; and simulation of complete control systems using the Comdyna Analog Controls Simulation Manifold for dynamic testing and digital computer interfacing.
- What Is a Hybrid Computer and Why
A short introductory article explaining the rationale for hybrid computing, contrasting analog and digital techniques, and describing a specific hybrid installation comprising EAI PACE 231R and 221R analog computers interfaced to a 4130 digital computer. The document lists the component inventory of the hybrid system (integrators, multipliers, potentiometers, function generators, A/D and D/A converters, logic trunks) and illustrates a practical application: using the hybrid system to model and optimise an industrial chemical process without interrupting production.
- Hybridsysteme: Automatisches Skalieren und statischer Test mit dem hybriden Interpreter HOI; Echtzeitsimulationen
A collection of German-language articles from the journal Angewandte Informatik covering EAI hybrid computer systems. The primary paper by K. Schwarze describes the HYTRAN Operations Interpreter (HOI), EAI's standard hybrid software, with emphasis on automatic amplitude/time scaling, off-line and on-line static testing, and automatic control of hybrid programs, demonstrated on a third-order ODE with variable coefficients using the EAI-690 system. Additional articles address hybrid computing in computer science education and real-time simulation of cable/rope mechanical systems and flight vehicle guidance.
- Mechanische Analog-Computer für schwere Flab-Kanonen, ca. 1930–1945: Technische Studien ab historischen Quellen — Funktionsweise des mechanischen Analog-Rechners SPERRY (USA)
A detailed German-language technical study by André Masson of Langenthal examining the internal workings of the Sperry mechanical analog director computer (ca. 1930–1945), acquired on a trial basis by the Swiss Army in 1935. The document explains the follow-pointer operating principle, the polar-to-rectangular coordinate conversion mechanism, cam-body (Formkörper) function solvers, disk integrators, and the electrical servo loop used for iterative impact-point prediction, with comparisons to German (Kommandogerät 36 and 40), British (Vickers), and Hungarian (Gamma-Juhász/Hasler) fire-control directors. The study is based on inspection of the surviving museum specimen at the Flieger-Flab-Museum Dübendorf and on Alfred Kuhlenkamp's 1943 book "Flak-Kommandogeräte."
- Hybrid Computing at Lockheed
Control Data Corporation application report describing Lockheed Missiles Systems Company's hybrid computing laboratory, which combines four CDC 8400 analog computers with a CDC 3200 digital computer. The system is used for missile trajectory simulation, Polaris submarine navigation studies, and other aerospace/defense problems requiring high-speed repetitive solutions. The brochure covers system configuration, operating software, and the advantages of hybrid computation over purely analog or digital approaches.
- Martin-Marietta Aerospace Simulation & Test Laboratory
Describes Martin-Marietta's Simulation & Test Laboratory (STL) Man-in-the-Loop Simulation System (MLUS), which uses a hybrid computer arrangement of three Sigma 5 digital computers and six EAI 231-RV analog computers to simulate the AAH (YAH-64), A-10, and F-16 aircraft. The system features an 80x40-foot terrain model scaled at 225:1 (helicopter) and 1200:1 (fixed-wing), a 6-DOF motion base with 18,000 lb payload capacity, and optical probe/TV systems for real-time closed-loop 6-degree-of-freedom simulation of air-to-surface weapon delivery missions.
- Analog Dialogue: Editor's Notes and Versatile New Module Y(Z/X)^m at Low Cost
A two-page excerpt from Analog Devices' Analog Dialogue journal, comprising an Editor's Notes page and an article on the Model 433 'Versatile New Module.' The article describes log-antilog techniques for performing Y(Z/X)^m computations (multiply, divide, exponentiate) with 0.5% FS error and 100:1 denominator range at low cost. Typical applications include true-rms measurement, curve fitting, linearization, and sophisticated analog instrumentation.
- Kunstfolien-Kondensatoren — Fertigungs-Übersicht
Product overview brochure from Dipl.-Ing. Kurt Schümann for the CKS series of plastic film (Kunstfolien) capacitors, covering round-wound and printed-circuit cast versions. Documents voltage ratings (63–630 V DC), capacitance ranges, tolerance options as tight as ±0.1–0.2%, three PCB mounting styles, and general electrical specifications including temperature range −10 to +70°C and isolation resistance ≥ 3 Tera-Ohm. Intended for developers requiring precision custom C-values outside standard catalog offerings.
- Rechenbeispiele: Einführung in die Analog-Rechentechnik
An 18-page German-language introductory workbook presenting annotated analog computer circuit examples covering summers, integrators, multiplier units (multiplication, division, squaring, square root), trigonometric and discontinuous function generation, and first- and second-order linear differential equations including a spring-mass system. All examples use dimensionless machine units (±1 = ±10 V) and include oscilloscope waveforms to validate the computed results.
- Vogel Analog Computer Schaltplan (Circuit Diagrams)
Two-page German-language schematic document for a Vogel analog computer, containing circuit diagrams for core computing elements (summers, integrators, inverters, multiplexer, diode function generator for sine approximation) and support circuits (DC/DC power converter, triangle wave generator, reference voltage supply, coefficient potentiometers, overload and polarity indicators, precision rectifier for meter display, and address selector switch). Primary op-amp used is the LF353 dual JFET-input device; precision reference is the REF01.
- The HYCOMP Hybrid Analog/Digital Computing System
Sales and technical brochure for the HYCOMP Hybrid Analog/Digital Computing System, a joint offering from Packard Bell Computer and Computer Products, Inc. The system combines the CPI Mark III analog computer with the Packard Bell PB440 stored-logic digital computer, linked via a high-speed analog-digital conversion subsystem (up to 128 A/D channels at 25 Kcps, 128 D/A channels at 100 Kcps, 14/15-bit resolution, better than 0.05% accuracy), binary signal control/sense lines, and the DIDAC automatic remote I/O controller. The brochure covers system architecture, the HYCOMP I/O controller, conversion link specifications, software macro commands for hybrid operation, and application areas including aerospace simulation, sampled-data systems, and optimization.
- PEK Analogrechner Stromläufe (38500-Serie)
A set of 10 engineering circuit-diagram sheets (Stromläufe) for the PEK 38500-series analog computer, covering drawing numbers Fs 38501 through Fs 38509. Sheets document the internal circuitry of individual plug-in computing modules including potentiometers, summing amplifiers, integrators, servo multipliers, a diode-network multiplier or function generator, precision rectifiers, a digital-voltmeter interface (TE 340), and the programming-panel wiring matrix. All drawings include component-value annotations, backplane connection tables, and German-language legend blocks.
- Multiplier/Divider Module 183 Schematic (Figure V-3)
Single-page schematic (Figure V-3) for the Model 183 Multiplier/Divider sub-circuit, part of the Practical Electronics analog computer construction series. The diagram shows the full circuit topology for an analog multiplier/divider module including op-amps, resistors, diodes, and associated components. Serves as the reference schematic for builders assembling or troubleshooting this specific analog computing element.
- Elektronischer Langzeitrechner endim 2000: Programmier- und Bedienungsanleitung
Programming and operating manual for the endim 2000 electronic long-time analog computer manufactured by VEB Rechenelektronik Glashütte (East Germany). Covers machine structure (amplifiers, multipliers, function generators, nonlinearities), operating modes (IC/Idle and Run), programming panel use, control and monitoring procedures, output evaluation with the function recorder, and technical appendix data for amplifiers, potentiometers, comparator, and electronic clock. The machine operates with computing voltages of ±100 V and supports up to 32 integrators/summators configurable from the programming panel.
- Computer Power Supply AS1104.2 Instruction Manual
Instruction manual for the Solartron AS1104.2 Computer Power Supply, a stabilised high-tension supply and valve heater supply designed for the Analogue Computing System. Covers performance specifications (output voltages including regulated ±100V and ±200V DC rails), installation and operating instructions, circuit description, maintenance and setting-up procedures, components list, and circuit diagrams with component location illustrations.
- Minispace Analogue Computer Operational Manual
Operational manual for the Solartron Minispace analogue computer, published by The Solartron Electronic Group Ltd, Thames Ditton, Surrey, England. Covers basic analogue computing techniques, machine setup and programming, patching, coefficient potentiometers, and computer functions including integrators and differentiators. Appendices provide specifications of the DC Amplifier AME1.8 and notes on computer limitations; applications addressed include solving single and coupled differential equations, servo-mechanism simulation, and weapons control system modelling.
- Servo Resolver Type TJ841 — Minispace: Technical Manual
Technical manual for the Solartron TJ841 Servo Resolver, a Minispace unit combining a servo multiplier with a resolver that provides sine and cosine outputs proportional to shaft angle. Covers installation, technical summary (±1% accuracy, 10–250 Hz AC input, 110 V/240 V mains), operational procedures, servo accuracy factors, and principles of operation including electrical multiplication and sine/cosine function derivation.
- Solartron Minispace Wiring Diagrams
A single-page hand-drawn wiring diagram for the Solartron Minispace analog computer. The sheet shows detailed interconnections between internal modules, power rails (including a -24V reference visible), patch points, and connectors, with handwritten annotations throughout. This appears to be one sheet from a larger set of wiring diagrams for the Minispace system.
- Donner Model 3000 Analog Computer Operating Handbook
Operating handbook for the Donner Model 3000 analog computer, a DC electronic differential analyzer with ten operational amplifiers (pentode-input, cathode-follower output) capable of solving differential equations. Covers specifications (open-loop gain >10,000, bandwidth to ~10,000 cps, output ±100V at 5mA), theory of operation including summing, integration, sign changing and scaling, operating instructions, and servicing. Includes schematic drawings for the power supply and amplifier/switching circuits, plus problem board layout.
- Model 3500 Analog Computer
Sales brochure for the Systron Donner Model 3500 Analog Computer, a compact 28-pound desktop unit designed for instruction, data reduction, signal generation, and process control. The machine features 10 stabilized plug-in amplifiers, a problem board with diode modules, single- and ten-turn potentiometers, regulated ±105 V power supplies, and a front-panel metering system; priced at $1,985. The brochure covers the system's components, specifications, application areas, accessories (including the Model 3530 Problem Board and Model 3570/3571 Potentiometer Strips), and basic installation configurations.
- Digital-Experimentiergerät DEX 100 — Beschreibung
Operator manual for the Telefunken DEX 100 Digital-Experimentiergerät (digital experimenter), a modular digital logic training and experimentation system also usable as a digital supplement to Telefunken desktop analog computers (RAT 700 NE, RA 741, RA 742). Covers the system's plug-in elements (RS/JK flip-flops, amplifiers, inverters, time elements, relay amplifiers, diode logic, clock generator), technical specifications (220 V / ~80 W, 584×550×410 mm, ~30 kg), programming field wiring with patch cords, and interfacing with analog computers. Includes circuit schematics for all module types.
- Digitalzusatz DEX 102 — Beschreibung und Bedienungsanleitung
Description and operating manual for the AEG-Telefunken Digitalzusatz DEX 102, a freely programmable digital logic unit designed as a companion to analogue computers. The 39-page manual covers technical specifications (clocked JK flip-flops, AND/OR interconnection elements, relay amplifiers, adjustable timer elements, and a multi-frequency clock generator), physical construction, programming via a patch-cord field, and connection to the RA 742 desk calculator for hybrid analogue-digital computation. Includes a full circuit diagram appendix and an element reference chart covering the DEX 100/DEX 102 family.
- Digitalzusatz DEX 102 — Informationsblatt
Two-page AEG/Telefunken product information sheet for the DEX 102 digital add-on unit designed to expand desk-type analog computers with digital capability for hybrid computation. Describes use cases (automated experiment control, machine computation with A/D and D/A conversion), special features (modular plug-in expansion, full integration into the analog computer desk chassis), and technical data including 10/12-bit converter options, 19-inch rack construction, 220 V/50 Hz power, and compatible AEG analog computer systems.
- Elektronischer Resolver ERV 801 — Bedienungsanleitung für die Zusammenschaltung mit einem Tischanalogrechner RA 742
Operating instructions for the Telefunken ERV 801 Electronic Resolver, an expansion module for the RA 742 desktop analog computer. The 7-page manual describes connection via parallel cable, four operating modes (free inverter amplifiers, multiplier, polar-to-Cartesian conversion, and Cartesian-to-polar conversion), jack color coding, and the small programming panel layout. Reference voltages are ±10 V representing ±180° for angular quantities.
- Telefunken ERV 801 — Elektronik, Rechenkomponenten: Schaltungszeichnungen (Prinzip und Belegungsübersicht)
Two-sheet engineering drawing set for the Telefunken ERV 801 analog computer. Sheet 1 (drawing SS-2005-650) is a principle-level schematic of the electronic computing components, showing operational amplifier stages, integrators, summers, and multiplier blocks with their interconnections. Sheet 2 is a Belegungsübersicht (patch/assignment overview table) mapping computing amplifiers, coefficient potentiometers, and PM3-type multipliers to their physical panel positions and signal routing designations.
- Hybrides Rechnersystem HRS 860 — Kurzbeschreibung
Brief description (Kurzbeschreibung) of the AEG-Telefunken HRS 860 Hybrid Computing System, which combines the TR 86 digital computer with the HKW 860 hybrid coupler network and the RA 770 (or RA 860 H) precision analog computer. Covers system architecture, operating modes (preparation, computation, output phases), hardware components including DA/AD converters (14-bit, ±0.01% LSB, 16 or 32 channels), and the software stack comprising the BESY 70/75/76 operating system, VEPRO traffic-control program, FORTRAN-HYBRID compiler, TST860 diagnostics, and VAMPIR potentiometer-logging utility.
- Extremwertsimulation eines Reglers für blockierungsfreies Bremsen auf dem Hybriden Präzisionsanalogrechner RA 770
A German-language technical article published under the AEG Datenverarbeitung / Analogrechner und Hybride Systeme imprint, describing the simulation of an anti-lock (blockage-free) brake controller using the hybrid precision analog computer RA 770. Authors Coinzel (TELEX, Heidelberg) and Maier (AEG-Telefunken, Konstanz) present the operating principle of the brake controller, the hybrid simulation structure combining the RA 770 analog computer with a digital computer for controller logic, and results of an extreme-value parameter search to optimize controller performance. Simulation results include vehicle velocity and stopping distance comparisons with and without the anti-lock controller.
- Demonstrationsbeispiel Nr. 5: Ball im Kasten
A 9-page AEG-Telefunken application note presenting Demonstration Example No. 5, which simulates a 2D elastic ball bouncing inside a box under gravity, damping, and elastic wall forces on an analog computer. The document covers the mathematical formulation of motion in x- and y-directions, analog circuit diagrams for four machine variants (RAT 700/RA 741/RA 742, RA 770, and RA 800 HYBRID), and a complete potentiometer list with coefficient values and machine-specific pot numbers. A sine-cosine circle generator is used to display the ball as a moving dot on an oscilloscope in repetitive-run mode with a ~30-second period.
- Erläuterungen zu der D1A-Reihe Analogrechner
A German-language introductory brochure from Telefunken explaining the principles and applications of the D1A-series analog computers, including the desktop RAT 740 and the precision RA 800 HYBRID system. Covers the basic computing elements (summing/integrating amplifiers, potentiometers, multipliers, function generators, and comparators) with circuit schematics, and illustrates practical application examples in control engineering, mechanical vibration simulation (automobile suspension), electrical engineering (transformer analysis), and process control.
- Zur numerischen Lösung von Dreikörnerproblemen des eingeschränkten Dreikörnerproblem
A German-language Telefunken application note presenting the analog computer solution of the restricted three-body problem (Earth–Moon system). The authors derive scaled machine equations from the equations of motion, select machine coefficients and time-scale factors, and provide a complete potentiometer list, variable (integrator) initial-condition list, and function-generator setting table for implementing the simulation on a Telefunken analog computer.
- Ermittlung der Kennwerte eines Prozesses mit Hilfe selbsteinstellender Systeme
A technical paper by Roland Konkart published under the AEG-Telefunken 'Datenverarbeitung — Analogrechner und Hybride Systeme' series, covering four methods for determining process parameters using self-adjusting (adaptive) systems: Gauss-Seidel iteration, iterative gradient, and continuous gradient methods (with both series and parallel models). The document derives the mathematical foundations for minimizing the squared-error objective function, presents analog computing circuit diagrams for each method, and works through a complete example of identifying the coefficients of a second-order system on a hybrid analog computer.
- Programmierung der Steuerbuchsen R, H und P bei den Tischanalogrechern RAT 700, RA 710, RAT 740 und RA 741
Six-page AEG-Telefunken application note describing the programming and use of control sockets R (compute), H (halt), and P (pause) on the RAT 700, RA 710, RAT 740, and RA 741 desktop analog computers. Explains the priority hierarchy among the three socket signals, their interaction with operating modes (single run vs. continuous compute), and illustrates five worked examples with relay-logic timing diagrams covering external halt sequencing, comparator-driven halt control, and pause command behavior.
- Tischanalogrechner und Zusatzgeräte — Kurzbeschreibung
A German-language brief description (Kurzbeschreibung) from AEG-TELEFUNKEN Datenverarbeitung covering two desktop analog computers — the RA 710 and RA 742 — along with four accessories: the DEX 109 digital voltmeter, MAT 740 patch-field networks, EVS 801 electronic resolver, and LZS 100 electronic audio output. Each section describes intended applications, special features, operating modes, computing elements, and a summary of functional counts (integrators, summers, multipliers, function generators). The document is a product overview rather than a detailed operator manual.
- Schwingungsberechnung eines Zwei-Massen-Systems
A 10-page AEG-Telefunken application note demonstrating analog computer simulation of a coupled two-mass spring-damper system subjected to a step disturbance. The document derives the equations of motion, performs amplitude and time scaling (λ = 10 s⁻¹, 10× time expansion), and presents full circuit schematics with potentiometer settings for three cases: linear (Case a), bilinear damper (Case b), and bilinear damper with dead-band spring nonlinearity (Case c). Oscilloscope result traces for mass deflections Y₁ and Y₂ are provided for all three cases.
- Nichtlineare Netzwerke NN 800 — Beschreibung und Bedienungsanleitung
Description and operating manual for the Telefunken NN 800 Nonlinear Networks plug-in module (Einschub) designed for use with the RA 800 and RA 800 Hybrid precision analog computers. The 28-page document covers mechanical construction, operating principles, and step-by-step operating instructions for the module's four function types: parabolic multipliers, fixed trigonometric functions (sin and cos at π/2 and π arguments), a logarithmic function (½ log 100x), and variable adjustable functions. Plug-in card (FB card) configurations for each function type are illustrated with detailed diagrams.
- Zweistrahloszillograph OMS 811 (Abschnitt 10)
Section 10 of a larger Telefunken analog computer system manual covering the OMS 811 dual-beam oscilloscope (Zweistrahloszillograph). Describes the instrument's purpose (display of analog computer output voltages up to 100 V), mechanical construction as a 19-inch rack slide-in unit, plug-in component population (amplifier units A-SV1A, switch units SP2A, sawtooth unit A-KM1, DN13-14 dual-beam CRT), electrical circuit design including power supply, high-voltage generation, input amplifiers, electronic channel switch, and maintenance/repair guidance.
- Elektronischer Analogrechner RA 463/2
Two-page Telefunken product brochure for the RA 463/2 electronic analog computer, describing it as an optoelectronic repetitive-operation machine with variable computing times from 0.1 to 172 seconds. The standard configuration includes 5 computing amplifiers, 1 function generator, 21 function potentiometers, 2 time-base generators, 31 motor-driven coefficient potentiometers, and 5 multipliers housed in one display cabinet and two computing cabinets. The document emphasizes modular construction enabling rapid component replacement and suitability for solving ordinary differential equations.
- Bedienungsanleitung zum Elektronischen Analogrechner RA 463/2
Complete operating manual (Bedienungsanleitung) for the Telefunken RA 463/2 fully electronic repetitive analog computer, covering general characteristics, commissioning, calibration procedures for mains devices, display device, and computing units, and detailed instructions for all nine computing operations including multiplication by constant, summation, integration, differentiation, multiplication, division, and arbitrary function generation. The 12-page German-language document includes a worked differential-equation example and repair/warranty information; the machine operates with computation intervals continuously variable between 0.1 and 112 seconds and ±100 V machine units.
- Telefunken RA 463/462 – Mechanik Zeichnungen (Mechanical Drawings)
A set of 13 mechanical front-panel layout drawings (scale 1:1 and 1:25) for the Telefunken RA 463/462 analog computer system, bearing Telefunken drawing numbers AH/MS 0.361 through AH/MS 0.373. Modules depicted include two computing amplifier variants (Rechenverstärker I and II), a multiplier, two function generator types, two potentiometer arrays, a timer, an oscilloscope display panel, two power supplies (±100V and +200V), a patch/switching panel, and a mains voltage regulator. The drawings show connector positions, meter placements, potentiometer arrangements, and control knob layouts at precise scale.
- Transistorisierter Tischanalogrechner RA 741 — Beschreibung
Operator description (Beschreibung) for the Telefunken RA 741 transistorized desktop analog computer. Covers technical overview, construction, component specifications (computing amplifiers, integrators, potentiometers, function generators, comparators), peripheral options, and a full table of base and optional configurations with prices in DM. Intended to inform users on operation, maintenance, and commissioning of the RA 741 analog computing system.
- Transistorisierter Tischanalogrechner RA 742 — Beschreibung
Comprehensive description and operating manual for the Telefunken RA 742 transistorized desk analog computer, covering technical overview, component complement (23 computing amplifiers in standard configuration, 19 coefficient potentiometers, multipliers, comparators, function generators), detailed technical specifications, and operating procedures. The document covers operation, maintenance, commissioning, and circuit descriptions, and notes that a separate computing guide is available for problem-solving methodology. Key specifications include ±10 V operating range, integrator drift below 50 µV/sec, and electronic integrator switching at 1 µs.
- Transistorisierter Tischanalogrechner RA 742 — Informationsblatt
AEG-Telefunken product information sheet for the RA 742 transistorized desktop analog computer, targeting university and industrial research computing centers. Covers key features, technical specifications (integrators, summers, function generators, parabolic multiplier, comparators, memory network), physical dimensions (670×550×500 mm, 105 kg), and a list of compatible add-on accessories including the DEX 102 digital add-on for hybrid computation.
- Kurzbeschreibung: Hybrider Präzisionsanalogrechner RA770
A German-language illustrated brochure providing a comprehensive overview of the AEG-TELEFUNKEN Hybrid Precision Analog Computer RA770, a fully transistorized 10V machine of 0.01% accuracy class capable of expanding to 142 computing amplifiers, 10 comparator amplifiers, and 84 coefficient potentiometers across up to 3 linked units. Covers computing elements (integrators, summers, multipliers, function networks, comparators, digital elements), programming fields, operation and control features including the digital supplement for automated run sequences, input/output peripherals (digital voltmeter, oscilloscope, XY plotter), construction, applications, technical data, and connectivity to the AEG-TELEFUNKEN TR86 digital computer via the HKW860 hybrid coupling unit.
- Hybrid Precision Analog Computer System RA 770 D — Operating Manual, Part 1
Part 1 of the operator's manual for the AEG-Telefunken RA 770D Hybrid Precision Analog Computer System, covering introduction, computer design and equipment, operating and control procedures, and programming. The RA 770D is a high-precision hybrid analog/digital computer featuring silicon-planar transistor amplifiers, low-drift operational amplifiers, and a modular drawer-based chassis expandable with additional computing units. The manual is organized into sections covering mechanical layout, computing elements (integrators, summers, multipliers, non-linear networks), operating controls, and programming techniques.
- Telefunken RA770 Operator's Manual — Chapter 2: Operation and Control (Section 3)
Section 3 of the Telefunken RA770 analog computer operator's manual, covering operation and control. Topics include decade selection, operating elements, timer configuration, digital control elements (push-buttons, analog patch panel, digital adapter unit, electronic resolvers, non-linear networks), and balancing and testing procedures. The section covers master and slave control panel configurations, the Digital Adapter Unit (DOU), and supply voltage testing.
- RA 800 Ergänzungsblätter: Multiplizierer, Winkelfunktionen und einstellbare Funktionen
Supplementary programming notes for the Telefunken RA 800 analog computer covering the parabolic multiplier networks (servo multiplier plug-in NN 800), fixed trigonometric function modules (sin x, sin πx, cos x, cos πx), the log₁₀₀ x logarithmic function, and adjustable function modules F(±X). Each section gives step-by-step wiring and programming instructions, including amplifier feedback configuration (330 pF capacitor plug, 20 kΩ normalization) and calibration of summing-point drift.
- Transistorisierter Tisch-Analogrechner RAT 700 — Beschreibung und Bedienungsanleitung
Operator manual for the Telefunken RAT 700 transistorized desktop analog computer (Tisch-Analogrechner), covering mechanical construction, modes of operation, technical specifications, and operating procedures. The RAT 700 is a fully transistorized (solid-state) desktop analog computer configurable from a basic setup (10 amplifiers, 20 potentiometers) to a full configuration (19 amplifiers plus multipliers and comparators), featuring chopper-stabilized computing amplifiers with drift below 20 µV at 40°C and less than 0.1% error up to 100 Hz. The manual also addresses coefficient potentiometers, parabola multipliers, free diodes, function generators, Schmitt triggers, repetitive computation, maintenance procedures, and fault finding.
- YEW Series 3300 Analog Computer
Product brochure for the Yokogawa Electric Works (YEW) Series 3300 family of all-solid-state analog computers, covering models 3301 through 3306 with 10 to 72 operational amplifiers in a modular building-block architecture. Describes the 'High Speed Repetitive Computation / Low Speed Conversion' approach unique to YEW, computing-element accuracy of 0.1%, and a full range of linear and non-linear computing elements including multipliers, diode function generators, and comparators. Auxiliary devices such as the waveform translator for X-Y recorder, cathode-ray oscilloscope, digital voltmeter, delay device, and logic assembly units are also described.
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