Factors That Affect the Strength of an Electromagnet

By J.T. Barett
Electromagnet.

Electromagnets are fundamentally useful devices, producing controllable amounts of magnetic force from an electric current. The strongest magnets are cool, have many turns of wire in their coils and use large amounts of current.

Description

Insulated wires.

An electromagnet is usually a coil of insulated wire wound around an iron core. It becomes magnetized when you run an electric current through it and loses magnetism when the current stops.

Turns

Pieces of a clock with electromagnet and coil.

To make an electromagnet stronger, you can wind a coil with more turns of wire. The number of turns multiplied by current in amperes gives ampere-turns, a factor that determines magnet strength.

Current

Wires coming through walls.

Generally, a magnet’s strength increases with greater electric current. At a certain point, the magnet will saturate, reaching a maximum strength.

Core

Iron metal.

An electromagnet will be stronger if you wind the wire turns around a metal core. The best metals are typically ferrous, or iron-bearing.

Temperature

Liquid nitrogen.

The current-carrying ability of wire improves with very low temperatures. The strongest magnets are made of superconductors cooled with liquefied nitrogen or helium.

About the Author

Chicago native J.T. Barett has a Bachelor of Science in physics from Northeastern Illinois University and has been writing since 1991. He has contributed to "Foresight Update," a nanotechnology newsletter from the Foresight Institute. He also contributed to the book, "Nanotechnology: Molecular Speculations on Global Abundance."