A magnet whose magnetic field is created by an electric current is known as Electromagnet. An electromagnet consists of a soft iron core wound with a coil of conductor wires.
When a direct electric current is passed through the coil of the electromagnet a magnetic field is created around it. Since the magnetic field of electromagnet is a function of electric current flowing through the coil hence, the magnetic field can be alter by changing the amount of electric current. And its polarity can be changed by changing the direction of electric current.
Electromagnets are temporary magnets because they can be demagnetized by reducing the current through the coil to zero. But still there may be some residual magnetism.
Electromagnets are used in
Electrical machines like generators, motors, transformers.
Relays and valves
Electric buzzers and bells
Loudspeakers and headphones
Memory Storage Devices like hard disks, VCRs, Tape recorders, magnetic drums etc.
Spacecraft Propulsion System
Most of the home electric appliances use electromagnets for their operation. Some of them include an electric fan, electric bell, magnetic locks, induction cooker, loudspeakers etc. In the electric fan, the electromagnetic induction keeps the fan motor rotating on which in turn makes the blades of the fan to rotate.
Also in an electric doorbell, when the button is pressed due to flow of current through the coil, electromagnet is created and the bell sounds.
In an induction cooker due to the electromagnetic induction, the body of the subject is heated by induced eddy currents.
The magnetic storage devices are used to store the binary data by magnetising and demagnetising the storage magnetic material of the device. Some examples of magnetic storage devices are hard disks, magnetic drums, magnetic tapes, VCR etc.
A well-known medical device MRI (Magnetic Resonance Imaging) uses electromagnets. The device can scan all the details in human body with help of electromagnetism.
All the communication devices like telephones and mobiles uses electromagnetic waves for their operation.
As the electric generators, transformers, electric motors and other inductive loads operate on the principle of electromagnetic induction. Hence, the electromagnets play a vital role in the generation, transmission and utilization of electricity.
Electromagnets are also used in industries for picking up and moving heavy iron objects like scrap iron and steel.