Electromagnetism

How Electromagnets Work

Electromagnets are similar to permanent magnets, but produce much stronger magnetic fields. Electric motors require this extra capacity.
To make an electromagnet, an iron rod is wrapped with insulated wire. The rod is called a "core".
Electric current flows through the wire when it is connected to a battery. This current magnetizes the iron core. Once magnetized, the core has both "N" and "S" poles. The poles of an electromagnet can be reversed by changing the direction of current flow.

When one or both ends of the wire at the battery are disconnected, current flow stops and the core loses its magnetism.
Alternating current changes directions on its own, causing the poles in the electromagnet to switch.