a core of magnetic material surrounded by a coil of wire through which an electric current is passed to magnetize the core.
usually large scale magnets for industrial use. The magnetism is created by passing an electric current through a metal coil. This means the magnetism can be easily controlled by switching the current on or off.
An iron bar placed through the center of the coiled wire would become a temporary magnet, as long as the electric current is flowing through the wire.(Basic Science/Magnetism/electricitymagnet/discussion013.htm)(Course Material/MagParticle/Equipment/equipment1.htm)