LCylipäästösuodatin

LCylipäästösuodatin, which translates to "low-pass filter" in English, is an electronic filter that passes signals with a frequency lower than a certain cutoff frequency and attenuates signals with frequencies higher than the cutoff frequency. The cutoff frequency is the point where the filter's response is reduced by 3 decibels.

An LC low-pass filter is constructed using an inductor (L) and a capacitor (C). The arrangement of these components determines its characteristics. A common configuration is a series inductor followed by a shunt capacitor. In this setup, the inductor opposes changes in current, and the capacitor opposes changes in voltage. At low frequencies, the capacitor's impedance is high, and the inductor's impedance is low, allowing the signal to pass through to the output with minimal attenuation. As the frequency increases, the capacitor's impedance decreases, and the inductor's impedance increases, effectively shunting the signal to ground and attenuating higher frequencies.

LC low-pass filters are widely used in various electronic applications, including power supply filtering to remove unwanted ripple and noise, audio crossovers to direct specific frequency ranges to different speaker drivers, and radio frequency circuits to select desired signals. Their advantages include good performance characteristics, efficiency, and the ability to handle significant power levels in some designs. The specific values of the inductor and capacitor are chosen based on the desired cutoff frequency and impedance matching requirements of the circuit.