NPN and PNP transistor tester (CB22146E)

This simple transistor tester was found in old English documentation. Suitable for general purpose transistors.

Acoustic Remote Control (CB17667E)
In fact, this is the circuit also known as “vox”, that is, a relay triggered by sound. This...
Siren (CB4381E)
This circuit was obtained from an English magazine from 1976. The signal from the circuit should be...
2-Transistor MW Radio (CB18397E)
This receiver for listening on the phone was found in a Japanese magazine in 1967. The circuit uses...