Found in American 90’s documentation, this circuit generates 300 Hz depending on the capacitors used. These components can be changed to obtain other frequencies.
This 70 kHz oscillator is used to erase tapes in pre-recording. The circuit is from 1968 General...
This circuit acts as a VU-meter when connected at the output of any audio amplifier, triggering a...
When the voltage exceeds the value given by the zener, this circuit from a 1990 documentation...