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 circuit was obtained in an old manual valid for practically any type of operational...
This circuit is found in an American documentation from the 80's. The circuit measures the power of...
This timer produces a continuous sound at the end of the timer set in potentiometer RV1. The...