What is an electromagnet?
As a counterpart to the permanent magnet, an electromagnet has a magnetic effect only at short distances and only through the action of electric current.
Electromagnets usually consist of an open iron core in a coil wound from wire. The current flowing through the wire generates a magnetic field that is concentrated in the hole in the center of the coil. As soon as the current is switched off, the magnetic field also disappears. In general, the further the distance from the coil, the lower the magnetic force. The iron core, which is usually made of a ferro- or ferrimagnetic material, concentrates the magnetic flux and makes the magnet stronger.
The first electromagnet was invented by British scientist William Sturgeon in 1824 and consisted of a simple piece of metal in the shape of a horseshoe around which copper wire was wound. In the following decades, the electromagnet was further improved and theories about its function were derived. Today, it is impossible to imagine many areas of industry and technology without the electromagnet.
Where are electromagnets used?
The best-known examples of the use of electromagnets in practice are induction stoves or magnetic separators, which are used primarily in scrap yards to separate magnetic material such as metal from non-magnetic objects. Other applications of electromagnets include motor technology, data storage devices, or magnetic levitation trains.