M302

This document is a schematic diagram for a "ONE SHOT DELAY M302" circuit, designed and copyrighted in 1967 by Digital Equipment Corporation (DEC).

Key details include:

• Purpose: The circuit is proprietary and furnished for test and maintenance purposes only.
• Components: It features a variety of electronic components including transistors (e.g., DEC 3639B/2N3639, 2N4274), diodes (e.g., D662/1N645, D664/1N3606), resistors, capacitors, and an inductor.
• Integrated Circuits: It specifically uses two DEC integrated circuits: E1 (DEC74H40N) and E2 (DEC7413N).
• Adjustable Elements: Two Helitrim potentiometers (R2 and R13) are included, likely for tuning the delay.
• Specifications: General component specifications are provided: capacitors are 100V, 10% (unless otherwise indicated); transistors are 2N4274; resistors are 1/4W, 5%; and diodes are D664. Specific exceptions are noted, such as C3 and C11 being Mylar, and 1.0 MFD capacitors being Tantalum.
• Pinouts: Pin 7 of ICs is designated as ground, and Pin 14 as +5V.
• Design History: The document includes a "Transistor & Diode Conversion Chart" and notes the drawing and engineering dates from mid-1967, with M. Haller as the drafter and L. White as the engineer.