The capacitors on this circuit determine the frequency that this circuit can detect. We can adapt it to work as an interesting shield detector for logic signals.
Found in a 90s Popular Electronics, this circuit uses a 741 to generate frequencies from 0.1 to 30...
This crystal-controlled oscillator was obtained from an American 1980s documentation. The circuit...
This circuit was originally intended for reading movie soundtracks. The circuit is from 1967 and...