Suitable for clandestine listening and in SMD assembly, this circuit was found in the Radio Eletronics magazine of August 1988. The listening is in headphones and the amplifier is electret.
We can control the frequency of an oscillator from digital circuits or from the output of a...
We recommend adding a 470-ohm resistor in series with the potentiometer in this dimmer circuit...
We found this circuit for old tape recorders in the December 1972 Radio Electronics magazine. The...