Electromagnets

Chris Soto

How does an electromagnet work?

The material of the core of the magnet is made of small regions called magnetic domains that act like tiny magnets. Before the current in the electromagnet is turned on, the domains in the iron core point in random directions, so their tiny magnetic fields cancel each other out, and the iron has no large scale magnetic field. When a current is passed through the wire wrapped around the iron, its magnetic field penetrates the iron, and causes the domains to turn, aligning parallel to the magnetic field, so their tiny magnetic fields add to the wire's field, creating a large magnetic field that extends into the space around the magnet. The larger the current passed through the wire coil, the more the domains align, and the stronger the magnetic field is. Finally all the domains are lined up, and further increases in current only cause slight increases in the magnetic field: this phenomenon is called saturation. An electromagnet consists of a length of conductive wire, mostly always copper, wrapped around a piece of metal. A current is introduced, either from a battery or another source of electricity, and flows through the wire. This creates a magnetic field around the coiled wire.

Examples of electromangets.

Microwaves, fire bells, and junkyard magnets are all electromagnets.
Electromagnets - How can electricity create a magnet?