Gold Finger Metal Detector PCB

The principle of high -frequency oscillator detecting metal

Adjusting the gain potentiometer of the high -frequency oscillator just makes the oscillator be in a critical oscillating state, which means that the oscillator just vibrates. When the detection coil L1 is close to the metal object, due to the electromagnetic induction phenomenon, vortex currents will be generated in the metal conductor, which will increase the energy loss in the oscillating circuit, weaken the positive feedback, the oscillating oscillator is weakened, and even the oscillation cannot be maintained. The minimum energy required is discontinued. If this change can be detected and converted into a sound signal, according to the sound of the sound, you can determine whether there are metal objects under the detection coil.