Electromagnetic Induction

Last Updated: December 20, 2016

Definition - What does Electromagnetic Induction mean?

Electromagnetic induction is the production of voltage or electromotive force due to a change in the magnetic field. Electromagnetic induction was discovered by Michael Faraday in the 1830s. Many electrical components and types of equipment work based on the principle of electromagnetic induction.

Techopedia explains Electromagnetic Induction

Electromagnetic induction can be generated in two ways, namely when the electric conductor is kept in a moving magnetic field and when the electric conductor is constantly moving within a static magnetic field. The phenomenon of electromagnetic induction was first discovered by Michael Faraday when he moved a bar magnet through an electric coil. He noticed a change in voltage of the circuit. He later deduced the factors that could influence the electromagnetic induction as the number of coils, the strength of the magnet, the changing magnetic fields and the speed of relative motion between coil & magnet.

The number of turns in the coils/wire is directly proportional to induced voltage. In other words, greater voltage is generated when the number of turns is higher. The changing magnetic field also influences the voltage which is induced. The speed of the relative motion between the coil and magnet was also found to affect the induced voltage or electromagnetic induction as rise in velocity cuts the lines of flux at a faster rate. This results in more induced electromagnetic force or voltage.

The induced voltage in an electromagnetic induction is described by the following equation as:

e = N × dΦdt


e = voltage induced (measured in volts)

t = time (measured in seconds)

N = number of turns found in the coil

Φ = magnetic flux (measured in Webers)

Many types of electrical equipment such as motors, generators and transformers function based on the principle of the electromagnetic induction.

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