## Series Inductor Filter – Circuit diagram, Waveforms and Working Principle

This post provides an information about series inductor filter. Before going to study series inductor filter it is necessary to understand what is meant by filter circuit?

Filter Circuit – Most of the electronic circuits require a dc voltage that is constant, similar to the voltage from a battery but the rectifiers cannot provide ripple free dc voltage. They provide a pulsating dc. The circuit used for filtering or smoothing out the AC variations from the rectified voltage is called as `Filter circuit.

## Series Inductor Filter

The circuit diagram and waveforms of series inductor filter are shown below:

Series Inductor Filter – An inductor opposes any change in the current flowing through it. Whenever the current through an inductor tends to change, a back emf is induced in it. This prevents the change in current.

Inductive reactance XL = 2p* f*L. For dc, f = 0, therefore direct current easily passes through the inductor to the load. The only opposition to dc is due to internal resistance of choke. The reactance increases with frequency. Therefore AC component is opposed. The output waveform shows a large dc component and a small AC component.

The operation of a series inductor filter depends upon the current through it. The higher the current flowing through it, the better is its filtering action. An increase in load current reduces the ripples.