This circuit was originally intended for reading movie soundtracks. The circuit is from 1967 and was found in an English publication. The sensor is semiconductor type.
We found this circuit in a 1975 publication. The power supply must be symmetrical, but other...
This circuit matches a high impedance input signal with a low impedance output. This circuit is...
When the power is on, the 1 µF capacitor charges slowly by R1 and P1 until then on trigger...