Electromagnet

An electromagnet is a type of magnet in which the magnetic field is produced by a flow of electric current. The magnetic field disappears when the current ceases.

Introduction

The simplest type of electromagnet is a coiled piece of wire. A coil forming the shape of a straight tube (similar to a corkscrew) is called a solenoid; a solenoid bent so that the ends meet is a toroid. Much stronger magnetic fields can be produced if a "core" of paramagnetic or ferromagnetic material (commonly iron) is placed inside the coil. The field produced by the coil causes the iron to magnetize and generate a field of its own. This field can be hundreds or thousands of times stronger than that of the coil itself.

Related Topics:
Coil - Wire - Corkscrew - Solenoid - Toroid - Core - Paramagnetic - Ferromagnetic - Iron

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Magnetic fields caused by coils of wire follow a form of the right-hand rule. If the fingers of the right hand are curled in the direction of current flow through the coil, the thumb points in the direction of the field inside the coil. The side of the magnet that the field lines emerge from is defined to be the north pole.

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