This simple tone control using two transistors was found in an Electronics Today International of the 90s. Transistors are general purpose NPN types, like the BC549 for greater gain.
This circuit is from the 1977 RCA Linear Integrated Circuits Manual. The circuit has a...
This circuit was found in 1980's Radio Electronics. The circuit produces a 1500 Hz modulate 35 kHz....
The maximum power of the controlled load depends on the triac used. The circuit is from a Radio...