What is a filter and different types of filter

What is a filter and different types of filter

When passive or active elements are designed to reject or select a band of frequencies then it is called filter. Filters are used to remove unwanted frequencies. There are two types of filter.

1) Active filter: – Active filters are filters that employ active devices such as transistors and operational amplifiers in combination with R, L, and C

2) Passive filter: – Passive filters are  those filters composed of series or parallel combination of R, L, and C elements.

Low pass filter: – The filter which passes only the frequencies below cutoff frequencies.

High pass filter: – The filter which passes only the frequencies above cutoff frequencies.