This simple circuit was found in a Japanese magazine in 1967. The circuit is listening on a headset and the coil is 50 + 50 turns of wire 28 or thinner on a ferrite rod.
We found this light relay circuit in year 2000 documentation. The relay is 6 V and the circuit...
We found this circuit in the Linear Technology Applications of 1997. The circuit uses components from...
We have dozens of similar projects in articles and circuits on this site. This is from Radio...