Discrete logic

3 boards

KiCad boards from 2 GitHub repositories tagged “discrete-logic”, the most starred first; open any of them in PCBKit.

6 layers290.7 × 322 mm
Board presignal
epatel/discrete6502
A MOS 6502 CPU rebuilt from 4,051 discrete transistors on a 291x322mm six-layer board that reproduces the original die layout
5,425 parts14
2 layers100 × 100 mm
Tach v1.0
maheen-ahmed1/OptoTACH
Precision non-contact optical tachometer (0–9999 RPM/RPS) built entirely with discrete CMOS logic & 555 timers; no microcontroller, no firmware. Includes KiCad EDA, 3D model, Python simulation, and bench validation.
99 parts
6 layers290.7 × 322 mm
Board routed golden
epatel/discrete6502
A MOS 6502 CPU rebuilt from 4,051 discrete transistors on a 291x322mm six-layer board that reproduces the original die layout
5,425 parts14

Board presignal