The expansion rate of this circuit is determined by R. The circuit can use any operational amplifier and the power supply must be symmetrical. Resistor R must be less than 10k.
This is the receiver circuit for the previous remote control published in the same Radio...
This circuit, for signals up to 1 MHz, is based on an RCA operational amplifier. The circuit was...
This frequency shift modulation circuit was found in the November 1994 issue of Electronics Now...