This circuit was found in a General Electric documentation from 1970. Equivalent transistors can be used. The maximum signal frequency for the indicated components is 250 kHz.
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...