Diode Tester (CB22137E)

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

Difference Amplifier (CB6429E)
Found in a Popular Electronics of the 90s this configuration can be seen elsewhere on our site....
Antenna tuner (CB6982E)
This circuit for receiving or transmitting low power was found in old American documentation. It is...
0 to12 V x 500 mA Power Supply (CB1391E )
This power supply can be implemented with a TIP32 providing an adjustable output at the 2k2...