what is filter?

Sometimes, Some kind of operations requires certain range of frequencies to perform its operation more efficiently.Thus a circuit is designed to perform such operation is called filter circuit.It is mostly needed in stereo systems,where certain range of audio frequency is required to be amplified.Also equalizers are used that allow the amplitude of several  frequency ranges to be adjusted to suit the listener's taste and acoustic properties of the listening area.Another one,Cross network which block certain ranges of frequencies from reaching speakers.                     

A tweeter (high-frequency speaker) is inefficient at reproducing low-frequency signals such as drum beats, so a crossover circuit is connected between the tweeter and the stereo's output terminals to block low-frequency signals, only passing high-frequency signals to the speaker's connection terminals. This gives better audio system efficiency and thus better performance. Both equalizers and crossover networks are examples of filters, designed to accomplish filtering of certain frequencies.

Practical Application:

Conditioning of non-sinusoidal voltage waveforms in POWER CIRCUIT.

some devices are sensitive to the harmonics in the power supply and hence requires power conditioning.

If there is a harmonics in the power supply,then the filter can be constructed that allows only the fundamental frequency by blocking the harmonics.

courtesy:allaboutcircuits.com


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