Electromagnet

Electromagnet is a temporary magnet formed when electric current flows through a wire or other conductor. Most electromagnets consist of wire wound around an iron core. This core is made from magnetically soft iron that loses its magnetism quickly when the electric current stops flowing through the wire.

Electromagnets drive electric doorbells, buzzers, and relays. They also produce the magnetic fields needed to make electric motors and generators work. Powerful industrial electromagnets lift heavy pieces of scrap iron. Specially designed electromagnets create the very strong magnetic fields that guide atomic particles along desired paths in particle accelerators.

In 1820, Danish physicist Hans Oersted discovered that an electric current produces a magnetic field. In 1825, English electrician William Sturgeon showed that an iron core strengthens a coil's magnetic field. American physicist Joseph Henry built the first practical electromagnet in the late 1820's.

Contributor: George Vahala, Ph.D., Associate Prof. of Physics, William and Mary College.

Electromagnet

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