Question

Why do we need filters in a power supply?

Answer 1

Hint:In the question, we need to know about the uses of filters in a regulated power supply. Firstly, we need to know about the power supply which is discussed in the solution part. Well, the purpose of using filters is to smooth out the ripple contained in the rectifier.

Complete answer:
Before knowing the need of filters, we should know about the power supply. So many electronic circuits or transistors require DC power supply. DC batteries are costly, so in such scenarios we need to make use of electronic circuits which can convert AC supply into DC supply using rectifier-filter systems.

Regulated power supply is one kind of electronic circuit, designed to provide the stable DC voltage of fixed values across load terminals irrespective of the load variations. A regulated power supply mainly includes:
-Step-down transformer
-Rectifier
-DC filter
-Regulator

Transformer is a device which transfers electrical energy from one circuit to another through the process of electromagnetic induction.Rectifier is an electrical device that converts AC into DC by using one or more p-n junction diodes. But the output of rectifiers is pulsating (means contains both AC component and DC component).

Hence, to remove all the AC components we use filters. Filter is a circuit which removes all the AC and allows only the DC component. Lastly, a regulator is an electronic device that maintains the voltage of a power source within acceptable limits.

Note:AC can also be read as alternating current which represents continuous current while DC is represented as direct current which contains discrete values. There are three most commonly used filters:
-Inductor filter
-Capacitor filter
-LC filter