Induced EMF

Definition - What does Induced EMF mean?

Induced EMF, also known as electromagnetic induction or EMF Induction is the production of voltage in a coil because of the change in a magnetic flux through a coil. An EMF can be induced in two ways, i.e., when an electric conductor is kept in a moving magnetic field or when the electric conductor is constantly moving within a static magnetic field. Many electrical components such as motors, galvanometer, generators, transformers, etc., work based on the principle of induced EMF.

Petropedia explains Induced EMF

The phenomenon of induced EMF was first discovered by Michael Faraday in 1830s 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 the coil and the magnet.

The number of turns in the coils is directly proportional to the induced voltage. In other words, greater voltage is generated when the number of turns is higher. Changing the 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, 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)
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