This circuit was suggested by Signetics in 1980s documentation. The circuit makes use of the hard-to-obtain component of our day. It is for reference 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...