Diode Tester (CB22137E)

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

Noise Bridges (CB25045E)
This circuit can be used as a noise canceller for communication receivers or even common ones. The...
Narrowband Audio Filter (CB20085E)
We found this circuit in an old American publication from the 1980s. Transistors can be...
Voltage Controlled Amplifier (CB24285E)
This circuit is part of a synthesizer that was published in parts in several issues of Radio...