This small audio amplifier circuit in complementary symmetry was found in the 1974 Mullard Databook. The output pair can also be the BD135 and 136.
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...