Low-Pass Filter

What Does Low-Pass Filter Mean?

Opposite in nature to a high-pass filter, a low-pass filter is a filter that allows signals with a frequency lower than the cut-off frequency (the frequency at which the output voltage is 70.7% of the source voltage) to pass through it. It also attenuates those signals whose frequency is higher than the cut-off frequency. In other words, low-pass filters help in removing short-term fluctuations, and provide a smoother form of signal.


Techopedia Explains Low-Pass Filter

In electronics, a low-pass filter is basically implemented in two ways: inductive low-pass filter and capacitive low-pass filter. The difference between the two lies in the way the components are arranged. In inductive low-pass filters, the inductors are inserted in series with the load, whereas in capacitive low-pass filters, the resistors are inserted in series and a capacitor is inserted in parallel to the load.

Many applications make use of low-pass filters as they are known to filter noise from a circuit. In power supply circuits, they are used to remove AC ripples. In order to block harmonic emissions that could potentially cause interference, radio transmitters make use of low-pass filters. They are also used as inputs in audio applications and certain loudspeakers in order to prevent the high pitches that are not produced efficiently. Low-pass filters are also used as integrators in electronic circuits.


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Margaret Rouse

Margaret Rouse is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical, business audience. Over the past twenty years her explanations have appeared on TechTarget websites and she's been cited as an authority in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine and Discovery Magazine.Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages. If you have a suggestion for a new definition or how to improve a technical explanation, please email Margaret or contact her…