This is a field strength meter found in an 80's Hands On. The circuit operates at frequencies up to 500 MHz and has a buzzer as its indicator. Can be used as a detector for spy transmitters.
This ultra-simple experimental receiver can be powered by a battery of water and salt. It was...
This circuit was sent by reader and collaborator Adriano Muniz Moura from Pirapora – MG. The...
This is an old traditional class B transistor circuit, using an output transformer to supply power...