We know that an electric current is formed when electrons flow through a conductor, such as a piece of metal wire. When a current flows through a wire a magnetic field is produced. The magnetic field that surrounds a current-carrying conductor can be demonstrated by placing magnetic compasses around a wire. The animation on the right shows how the needles are deflected in response to the strong magnetic field created by the current. The needles align themselves with the magnetic field produced by the current and show it to be a pattern of concentric circles about the wire.



The magnetic field lines form the concentric circle pattern shown on the left.
The direction of the magnetic field changes when the current reverses direction.

Uses of electromagnets-electric motor

Use of electromagnets-speakers and microphones


The elastic band provides the tension to automatically close the gate. Metal contacts that complete the circuit and cause the light to glow when the gate is shut The light indicating if the gate is open or closed An electromagnet that activates the lock The bolt that is lifted through a scre eye by the electromagnet The gate