RC Filter Calculator

Electronics Engineering Tool for Low Pass, High Pass, and Band Pass Filters

Calculate Cutoff Frequency (fc)

RC Low Pass and High Pass Filter Circuit Schematics

Cutoff Frequency (fc)

159.15
Hz

fc = 1 / (2πRC)

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How RC Filters Work

An RC circuit can be used to filter out specific frequencies from a complex signal. In a Low Pass Filter, the resistor is in series with the signal and the capacitor is connected to ground, allowing low frequencies to pass while attenuating high frequencies. In a High Pass Filter, the positions are swapped.

The Cutoff Frequency (fc) is the point at which the signal power is attenuated by half (-3dB point). The mathematical formula used by this calculator is: fc = 1 / (2 * π * R * C).

What is a Band Pass Filter?

A Band Pass Filter allows a specific range of frequencies to pass through while attenuating frequencies outside this range. It can be constructed passively by cascading a High Pass filter (which sets the lower cutoff frequency, fLow) with a Low Pass filter (which sets the upper cutoff frequency, fHigh). For this cascading method to work effectively without significant loading effects, the impedance of the second stage should be considerably higher than the first stage.