This circuit is from Radio Electronics from March 1977. The integrated circuit is from that time and the circuit is intended for an infrared audio link. The modulation is in pulse frequency.
Other operational amplifiers in the series, such as the MC34072, MC34074, MC35071, MC35072,...
We can use this circuit to connect low impedance microphones and even small speakers used as a...
September 2016 - It can be purchased from Mouser Electornics the iW1818 of Dialog Semiconductor, a...