What is an Electromagnet?
An electromagnet is a magnet in which the magnetic field is created by passing an electric current. They usually consist of an insulated wire wound into a coil. You can wind lots of loops of a wire together to make a coil. There is also a magnetic material at the centre of the coil, which is called the core of the electromagnet. And, in most electromagnets, cores are made from iron. An electromagnet where there is no core at the centre is called a solenoid.
Properties of electromagnets:
Electromagnets are temporary magenets because their magnetic field exists only as long as an electric current flows through their coil. If there is no current flowing through the coil, there will be no magnetic field. This property of electromagnets makes them useful in some applications where scientists and engineers want to control the magnetic fields.
The strength of an electromagnet depends, mainly, on two important factors:
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The number of turns in the coil. A larger number of turns produces a stronger magnetic field.
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The amount of current flowing through the coil. An increased amount of current results in a stronger magnetic field.
Applications of electromagnets:
Electromagnets are used in a number of everyday devices such as electric bells, electrically controlled door locks and loudspeakers and headphones.