Analog filter is typically used in electronics and is considered as a basic building block of signal processing. These analog filters are used to separate audio signals before applying to loudspeakers. To separate and to combine several telephone conversations onto a single channel can be done using analog filters. To select a particular radio station from the radio receiver by rejecting all other channels can be done using analog filters.
The circuits built using RC, RL, or RLC circuits.
The circuits that employ one or more op-amps in the design an addition to resistors and capacitors