What Is Active Filter Circuit?

Hint:Active Filters are the filters that contain active components such as operational amplifiers (OP-AMPs), transistors or FETs within the circuit. Now let’s see in detail about the active filters and how it is helpful.

Complete step by step solution:
Before we talk about active filters first of all we need to know about filters. A filter is a circuit that is capable of passing or amplifying a certain frequency while attenuating other frequencies. Thus, a filter can get the important frequencies from signals that also contain undesirable or irrelevant frequencies.

In the field of electronics, there are many practical applications for filters which are as follows. Filters are used in radio communications to obtain only the desired signal while rejecting all other signals. These are used to eliminate undesired high frequencies (i.e., noise) that are present on AC input lines in DC power supplies. Filters are used to convert the signals from analog to digital using analog to digital converters.

Now let’s move on to the active filters. Active filters draw their power from an external power source and use it to boost or amplify the output signal and it generally uses an operational amplifier. To shape or alter the frequency response curve filter amplification is used which produces a more selective output response which in turn makes the output bandwidth of the filter much narrower.

There are four types of active filters those are,
1. Active Low Pass Filter.
2. Active High Pass Filter.
3. Active Band Pass Filter.
4. Active Band Stop Filter.

Note:Then the main difference between a passive and an active filter is its amplification. Active filters are mostly used in communication systems for suppressing noise, to isolate a communication of signal from various channels.