English translation
PEK 38500 Analog Computer — Circuit Diagrams (Stromläufe)
This file is an English translation/description of the original German-language scanned schematic document.
Overview
This document is a set of 10 circuit diagram sheets (German: Stromläufe) for the PEK 38500-series analog computer. Each sheet bears a drawing number in the “Fs 385xx-01-01” series and depicts the internal circuitry of one computing or auxiliary module. The drawings are engineering-style schematics with component designations, connection tables, and legend blocks in German.
Sheet 1 — Potentiometer (Drawing Fs 38501-01-01)
Title block: Potentiometer
This sheet shows multiple potentiometer circuit symbols arranged in rows, together with a parts/connection list (German: Bauteileliste / Anschlüsse). The layout indicates the wiring scheme for a bank of precision potentiometers used as coefficient setters in the analog computer. A legend block in the upper right gives the revision history and drawing number.
Sheet 2 — Step Switch / Selector (Drawing Fs 38501 variant)
Title block: (Stufenwähler or similar selector module)
This sheet depicts the main amplifier/selector circuit of the analog computer. A detailed circuit schematic in the lower-left shows operational amplifier stages, transistor switching circuits, and passive networks. The right portion contains a large wiring matrix/connection table showing how multiple plug-in cards (labeled Platine 1 through Platine 5 or similar) connect to the backplane. Revision and drawing metadata appear in the upper-right title block.
Sheet 3 — Integrator (Drawing Fs 38505-01-01)
Title block: Integrator (Integrierer)
Shows two integrator computing elements. Each integrator consists of an operational amplifier with feedback capacitor(s) and input resistors. The schematic includes the control logic for initial-condition (IC) and operate/hold modes, implemented with relay contacts or electronic switches. Component values (resistors in kΩ, capacitors in µF) are noted on the diagram. Inputs and outputs are labeled with standard analog-computer notation.
Sheet 4 — Summing Amplifier (Drawing Fs 38504-01-01 / Summierer 2)
Title block: Summing Amplifier (Summiererverstärker / Summierer)
A multi-input summing amplifier circuit. The left portion shows the detailed schematic with the operational amplifier, precision feedback resistor, multiple input resistors, and offset-trim network. The right portion is a large connection matrix similar to Sheet 2, showing how multiple plug-in cards connect to the backplane. This module provides the basic algebraic summing and inverting-amplifier function of the computer.
Sheet 5 — Diode Multiplier / Function Generator (Drawing Fs 38505-01-01 variant)
Title block: Diode multiplier or quarter-square multiplier
A complex schematic showing multiple operational amplifiers, diode networks, and associated resistor ladders. This appears to be either a quarter-square multiplier or a diode-function-generator module. Upper portion contains a detailed connection/component table. The lower-left circuit shows the core signal-processing network, while the right side includes additional amplifier stages.
Sheet 6 — Programming Panel Wiring (Drawing Fs 38506-01-01)
Title block: Programming Panel (Programmierfeld)
A wiring matrix diagram for the analog computer’s programming/patch panel. The sheet consists almost entirely of connection tables arranged in rows and columns, showing how the various computing element inputs and outputs connect through the patch panel. Small circuit symbol legends appear in the upper portion. This is a wiring/interconnect diagram rather than a conventional circuit schematic.
Sheet 7 — Servo Multiplier (Drawing Fs 38507-01-01)
Title block: Servo Multiplier (SERVO-Multiplizierer)
Shows two servo-type multiplier modules. Each module includes an operational amplifier, servo-motor drive circuit, and feedback potentiometer arrangement. A small block diagram in the upper-right illustrates the servo loop concept. The lower portion shows a second servo circuit variant. Servo multipliers provide the product of two variables using a motorized potentiometer.
Sheet 8 — Measurement Instrument — Digital Voltmeter (Drawing Fs 38508-01-01)
Title block: Measurement Instrument (Meßinstrument)
A relatively simple schematic showing the interface circuit for a Digital Voltmeter, Type TE 340 connected to the analog computer output. The circuit includes input protection resistors, range-switching, and connector wiring. A note on the drawing states that components R1, R2, R3 must be adjusted when the unit is installed, and that the final values must be recorded on the device. The TE 340 is shown as a block labeled “Digitalvoltmeter Typ TE 340.”
Sheet 9 — Rectifier or Switching Circuit (Drawing Fs 38509-01-01)
Title block: Rectifier or Circuit (Gleichrichter oder Schaltung)
Two circuit schematics are shown. The upper circuit is a precision absolute-value (rectifier) circuit using operational amplifiers and diodes. The lower circuit appears to be a comparator or limiter stage. Both circuits use the same operational amplifier type found throughout the machine. Component values are annotated on the schematic.
Sheet 10 — Waveform Store / Auxiliary Module
Title block: (Kurvenformspeicher or similar auxiliary function)
The final sheet shows another multi-amplifier module, possibly a track-and-hold or waveform storage circuit. Two symmetric circuit blocks appear side by side, each containing an operational amplifier with capacitive storage elements, switching transistors, and associated passive networks. Drawing number and title are partially legible in the title block.
[Translation covers the first 10 pages (all pages); this constitutes the complete document.]