This simple metronome, from 1985 documentation uses only transistors and has two settings. For voltages above 6 V, up to 12 V, replace the BC557 with a BD136.
Two potentiometers mounted at right angles, so that they can be operated by a lever, form a very...
The integrated circuit and configuration are uncommon. However, the sound quality is good. The...
Found in General Electric's 1969 documentation, this circuit uses two Foto Darlingtons to control...