Inductors : Basically , inductors are coils that have large inductance . They oppose the change of current flowing through them , and are used in power supplies for filtering out ripples .
Their principle of working is explained below .
We know that the flow of current through a conductor is accompanied by magnetic effects . The transfer of electrical energy to the magnetic field represents work done by the source of emf . power is required for doing work , and since power is equal to current multiplied by voltage ,there must be a voltage drop in the circuit during the time which energy is being stored in the field .This voltage '' drop'' (which has nothing to do with the voltage drop in any resistance in the circuit ) is the result of an opposing voltage value .When the field becomes constant the induced emf or back emf disappears,since no further energy is being stored . Since the induced emf opposes the emf of the source , it tends to prevent the current from rising rapidly when the circuits is closed .The amplitude of the induced emf is proportional to the rate at which the current is changing and to a constant associated with the circuit itself , called the inductance of the circuit .
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