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.

Proximity Detector (CB11566E)
This circuit is from a 1965 Argentine publication (Radio Chassis Television). The original...
Microammeter with the 709 IC (CB24197E)
Using a 709 integrated circuit this circuit was found in the June 1972 issue of Radio Electronics...
Temperature sensor shield (CB5093E)
This circuit was found in an old publication and can be adapted for use with modern...