## Why inductors are using in a filtering circuit and VFDs

As we know the inductor stores the energy and release the same in terms of magnetic field. Also, the voltage across an inductor is V, the inductance of the coil L and the current flowing through an inductor is i. here I change with respect to time. Hence the Voltage V is..

Generally, instantaneous value is defined as the value of the signal is varied from one level to another level within the very short time typically zero..

Here the current flow through the inductor changes instantly then time=0, hence dt=0

In Normal condition, The voltage across the inductor, V is equal to

Apply dt=0, because of the instantaneous changes,

If the current through the inductor changes instantly, the voltage across the inductor is infinity. It is practically impossible. Therefore, the current through the inductor cannot change instantaneously.

Also see: Why DC supply should not give to the transformer.

Application:

This principle is used in many applications.

**VFD Chokes:**

VFD consist of fully electronics circuit such as the thyristor, diodes, Integrated circuits etc. the small changes in the current may lead to The chokes are made up of the heavy inductive coil, it is used to filter out the incoming power supply’s current ripple. See Full Details.

**Lighting chokes**

The coil wound inductor use to generate high current across the filament.

- Wave shaping circuit:

Inductor use to filter DC-AC inverter’s output current.