This common circuit using operational amplifiers was found in the 1993 issue of Radio Electronics Special Projects. The circuit is sandwiched between the pickup and the amplifier input.
This simple electronic toy organ produces an interesting sound, which can be used by the most...
This SCR circuit was found in an American 1980s documentation. The circuit is still current,...
The sensor of this circuit can be any phototransistor and the SCR can be the TIC106. The circuit and...