
The simplest form of a metal detector was included an oscillator which produced an alternating current and magnetic field that passes through a coil. When a piece of electrically conductive metal is closed to the coil, eddy currents will be induced in the metal, to form create its own magnetic field as a metal detector. It is used to detect the metallic object and used for Mine finding Mechanism in war. It is short range device and between 9 inch and below, it can detect any metal between this range such as gold, tin, steel and any electropositive elements.