A metal
detector is a device which responds to metal that may not be readily
apparent.

The simplest form of a metal detector consists of
an oscillator
producing an alternating current that passes through a coil producing an
alternating magnetic field. If a piece of electrically
conductive metal is close to the coil, eddy currents
will be induced in the metal, and this produces an alternating magnetic field
of its own. If another coil is used to measure the magnetic field (acting as a magnetometer),
the change in the magnetic field due to the metallic object can be detected.

Location

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