Electro magnetism

Magnetic field

The area around a magnet or electromagnet where the effects of the magnetic force can be felt.

Magnetic flux

The number of magnetic lines of force set up in a magnetic circuit, measured in Webers (Wb).

Magnetic flux density

A measure of how compacted the lines of flux are, measured in teslas (T) or webers per square metre (Wb/m²).

Maxwell's screw rule

Describes the direction of the magnetic field produced by a current, using the analogy of driving a screw in the direction of current flow.

Solenoid

A coil wound into a tightly packed helix, producing a magnetic field when an electric current passes through it.

Electromagnet

A type of magnet where the magnetic field is produced by an electric current.

Relay

An electrically operated switch used to control a circuit with a low-power signal.

Contactor

A type of relay that can handle high power loads, used to directly control electric motors or other high-power devices.

Attraction

The force by which one object brings another closer.

Repulsion

The force by which one object pushes another away.