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.
This circuit was found in American documentation from the 1980s. Its purpose is to use a 170 MHz...
This simple circuit can be used to power a simple communication system using ordinary telephones....
This simple audio signal tracer or follower can be made with a BC548 instead of the original...