MAGNETISM:

Approximately 70% of Automotive electrical devices use the principle of magnetism. It is important, therefore, that you understand some of the basic laws involved.

Magnetism is an invisible force which attracts certain metals. The area that is under the influence of this magnetic force or flux is called a magnetic field. The strength of the magnetic field is governed by the number of lines of magnetic force it contains.

A magnet has a polarity known as a North Pole and South Pole. The magnetic flux of field travels from the South Pole of the magnet internally to the north pole and then externally from the north pole to the South Pole. In other words, magnetic lines of force always flow out of the north pole into the South Pole.

The polarity of magnets becomes evident when two magnets are placed close to each other with unlike poles opposite each other. The two magnets are drawn Together by the action of the combined fields making one large magnetic field.

If the magnets are held close together with their like poles opposite each other, the magnets tend to repel each other, with each magnet maintaining its own magnetic field.

You will see how magnetism is used to operate electrical units as this course proceeds.

MAGNETISM