Using operational amplifiers of the time, we found this circuit in documentation from the 90s. The configuration can be adapted to use modern operational amplifiers.
One of the first transistor amplifiers with transformerless output but using a 45-ohm speaker. This...
This modulator circuit is nothing more than an audio amplifier that serves to modulate amplitude...
Found in old documentation, this circuit makes use of amplifiers of the time, uncommon today. Next...