Sallen-Key Low-Pass Filter Calculator

This calculator is used to determine the value of the capacitors needed for a second-order unity-gain Sallen-Key low pass filter.

Input the selected values for the desired cutoff frequency and the resistors. R1 and R2 will be equal. Hit the Calculate button for the capacitor values.

Note that C2 is always double the value of C1. (rounded)
The values are for a Butterworth response, which has maximally flat passband
frequency response. The output decreases at -12 dB per octave above the cutoff frequency.

Need to Convert Voltage Gain to Decibels?

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