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.
We found this circuit in an old neon lamp application manual. The circuit stores a call. The...
Poptronics recommends this circuit for use in the car when the headlights are left on. The circuit...
We found this circuit in a 1981 publication, when it was still possible to find 22.5 V batteries (used...