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RC Low-Pass Filter

Given R and C, calculate the cutoff (-3dB) frequency of a low-pass filter.


rc filter

Enter Components

R Ohms
C Farads
fc = 1/(2*pi*R*C)
fc (Hz)

Download / Basics

To run or modify on your PC, download a simple version of this file with image (*.zip).
For a quick tour of some JavaScript / HTML basics, check out Inside the Code.

JavaScript / HTML

// calc fc
function getfc_RC_Fil() {
	// get values directly from form
	var R=document.myForm.R.value
	var C=document.myForm.C.value
	var fc
    // calc
    // place in text box
    document.myForm.fc.value = (fc).toPrecision(4);