Diode Tester (CB22137E)

This diode tester was found in an English publication from the 1980s. Transistors are general-purpose types of the time.

AC Automatic Activation (CB14969E)
When the equipment powered by the SO1 socket is turned on, the SO2 socket is automatically...
Small hearing aid amplifier (CB23860E)
This microcircuit that fits in an aspirin box was published in Radio Electronics magazine in...
Phase 2 inverter (CB22233E)
This circuit was found in an American publication from the 50's. The transistors are made of...