absorption detector

[brasilpb]

This is a simple absorption metal detector circuit, but I believe that with some modifications to make a good LRL, mineoro's fg also have an oscillator in the resonant input circuit. With a suitable coil, the device will detect old metals in which the hallo effect is present. The oscillator circuit works with a very low current, so that the magnetic field is as little as possible, and that in the presence of metals a part of this magnetic field is stolen from the coil, reducing the wave amplitude, that alone was good, more it was possible to amplify this signal even more, so that it can function as a sensitive low frequency receiver, where if it had some radiated signal, it would be mixed with the signal of this oscillator that would later be demodulated and amplified again, having as a final sensitive receiver, which could pick up some anomaly in the distance.
https://makingcircuits.com/blog/ferr...etal-detector/