This circuit was found in a 1964 Electronic Design. The transistor may be a current equivalent of general use. The frequency ranges from 100 to 150 Hz.
This circuit is from an American 80's documentation. The transistor is general purpose,...
This circuit is from 1994, from a technical documentation from National Semiconductor, but can be...
This is the factory setting (National Semiconductor) of the TDA2006 as an audio amplifier. The...