We found this circuit in a 1968 US documentation. The power FET is a component of the time and the current is 4.5 mA only.
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...