Low Pass Filter

A low-pass filter (LPF) is a filter that passes signals with a frequency lower than a certain cutoff frequency.

Click on the values to change them! E.g. change "10k" to "20k". All equations and figures in the step response will adjust immediately!

RC LR

Circuit of low-pass filter

Cut-Off Frequency: $f_c = \frac{1}{2\pi R C} =$ 159 Hz
Time-Constant $\tau$ $= RC = \frac{1}{2\pi f_C} =$ 6.28ms
Amplitude at $f_c$ is $U(f_c)=\frac{U(0)}{\sqrt{2}} =$ 3.54 V
Dynamic: $I_C = C \cdot \dot U_C$

Filter Response:

Step Response Frequency Response

$V_{\mathrm{out}} = V_{\mathrm{max}} \left( 1 - \exp( - t/\tau) \right)$
$V_{\mathrm{out}}$ will reach $V_{\mathrm{max}}$ after 3 to $4 \tau$.