This circuit is from a 1980s Motorola documentation. The circuit makes use of old components that can in some cases be exchanged for modern equivalents.
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...