But the inductor has different resistance for different frequency signals as capacitors do. That means how the resistance or impedance of the inductor behaves with frequency passing through it. The LR filter circuit works on the principle of inductive reactance. Active filters are filter circuits that consist of an operational amplifier with a combination of passive components and provide LRC-like filtering at lower frequencies.įig. In these cases, an active filter comes into play. But at lower frequencies (below 1MHz), the inductor values increase and size, which makes the design bulky.
As pass filters don’t filter any frequency components from complex signals, they just add a linear phase shift in each frequency component of a signal.Īt higher frequencies (greater than MHz), these filters consist of passive components like inductors, capacitors, and resistors and are called RLC filters. Bandpass filters are used in power supply systems to suppress the noise of 50 Hz.Īll pass filters are used to add time delay in each frequency component of a complex signal. In data acquisition systems, low-pass noise filters and anti-aliasing low-pass filters are required for signal conditioning. In the central telephone offices, high-frequency (hundreds of MHz)bandpass filters are used for channel selection. Filters are used in various fields including telecommunications where bandpass filters are used in speech recognition and modems in the audio frequency range (0 Hz to 20KHz).