With this circuit it is possible to select transistors and their compliant test. Or circuit consists of an oscillator. Or transformer of the type found in old transistor radios.
The circuit shown is from an old European publication. In it we have the way to activate a relay...
We found this circuit in a European publication from the 1990s. Transistors are still common types...
This circuit was found in an American documentation and can be added to common amplifiers of any...