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.
Found in Radio Electronics from the 90s, this circuit has a power given by the output amplifier. The...
This circuit was obtained in a 1982 English magazine. The purpose of this circuit is to interface...
We found this circuit in an English publication of 1976. It can be easily assembled by changing the...