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.
Found in 90's Electronic Engineering, this circuit produces a pulse with a delay that depends on R3...
This circuit was found in the December 1984 issue of Radio Electronics magazine. The circuit has a...
Found in 90s Radio Electronics, this circuit is intended for amplifying analog video signals....