For an 8 ohm load, this Motorola circuit was found in a 1968 documentation. The transistors are of the time and the power supply must be symmetrical.
Tone controls for audio applications can also be considered filters that must attenuate certain...
We found this basic circuit of a relaxation oscillator with unijunction transistor in a 1976...
This unusual unijunction transistor SCR firing circuit was found in a General Electric...