Build Your Own Metal Detector with an Arduino

Learn how to build a metal detector using a Colpitts oscillator and an Arduino. In the above circuit, the series capacitor and inductor form a tank circuit. In an ideal tank circuit, the electrical energy dissipated from the capacitor will charge the inductor, storing the energy as a magnetic field. After the capacitor discharges, the magnetic field built up by the inductor begins to collapse, creating a current flow in the opposite direction from which it was charged with. This, in turn, charges the capacitor once again. When the magnetic field has collapsed, this cycle repeats. The continuous energy build-up between the capacitor and inductor creates an oscillating current between the two components.”

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