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Postby TGTS0907129» Concept of self inductance

Explain the concept of self inductance


There is an emf induced in a coil wherever there is a change in the magnetic flux threading the coil. In the examples there considered the source of the flux was outside the coil in which the change occurred. But even where there is a changed in the current in the coil itself, the flux threading the coil changes and an emf in induced in the coil, such an emf induced by changes of current in the coil itself, is called an emf of self-induction. In accordance with Lenz’s law, the emf of self-induction is always in such a direction as to oppose the change that caused it.
Which has N turns, an average circumference l, and in which there is a steady current I. The flux density within the toroid is given as B = μ0 NI/l and the flux threading the coil is Φ = BA = (μ0 NI/l)A. If the current in the coil is changed by an amount ?I in time ?t, there will be an induced emf whose average value during the time is

The induced emf is proportional to the rate of change of current. We may express the instantaneous induced emf eL in terms of the instantaneous rate of change of current, using small e and i to represent instantaneous values.

By TGTT24071251 on 10/12/2015 12:50:59 AM
TGTS0907129 on 10/12/2015 12:42:47 AM

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