Theory for metal detector

Metal Detector - The metal detector uses the principle of electromagnetic induction to generate a rapidly changing magnetic field using a coil that has an alternating current. This magnetic field can induce eddy currents inside metal objects. The eddy current will generate a magnetic field, which in turn affects the original magnetic field, causing the detector to beep. The accuracy and reliability of metal detectors depend on the stability of the electromagnetic transmitter frequency and is typically used from 80 to 800 kHz. The lower the operating frequency, the better the detection performance of iron; the higher the operating frequency, the better the detection performance of high carbon steel. The sensitivity of the detector decreases as the detection range increases, and the magnitude of the induced signal depends on the size and conductivity of the metal particles.