How Electric Currents Make Magnetic Fields

An electric current must flow through an electromagnet if the magnet is to work. The current makes the magnetic field.

The Field of an electromagnet

The magnetic field lines came out of one end of the electromagnet. This is its north pole.

The field lines go round and back into the other and of the electromagnet. This is its south pole.

Current and field

Image Source:https://media.sciencephoto.com/image/h4150003/800wm

Hans Christian Oersted was a Danish scientist. He thought that there might be a connection between electricity and magnetism.

One day, in 1820, he was giving a lecture about electric circuits. A magnetic compass was lying nearby on the bench. When he switched on his circuit, he noticed that the compass needle changed direction.

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Oersted had discovered that whenever an electric current flows in a wire it makes a magnetic field around it. The photograph shows a modern version of his experiment.

When the switch is closed, the battery makes a current flow in the wire. The compass needle moves round, just as in Oersted’s experiment.

How and electromagnet works

The magnetic field around a wire is quite weak. An electromagnet is a clever idea because, by winding the wire into a coil, you concentrate the magnetic field into a smaller space, making it much stronger.