PC address decoder (CB20536E)

This TTL decoder circuit for PC ports was found in a document from 1992. The power supply can be PC's own circuit.

High Impedance Probe (CB6454E)
Originally suggested by Electronic Design in a 1965 documentation for use with oscilloscopes, this probe has...
Integrated FM Radio (CB14571E)
This circuit uses currently uncommon components, including the 10.7 MHz (FI) filter. This circuit was...
LASCR Tachometer (CB9351E)
This optical tachometer with LASCR was found in a 1965 General Electric documentation. The diode at...