Using the 741 this basic circuit was found in the November 1973 Radio Electronics magazine. The power supply must be symmetrical. The components can be recalculated for other frequencies.
This circuit, from the 90's, is intended for operation with vinyl record players of the time, as...
This circuit, in fact, what it does is a reactivation of the batteries through a brief pulsating...
This circuit, for signals up to 1 MHz, is based on an RCA operational amplifier. The circuit was...