๐๏ธ RC Filter Designer
Design low-pass, high-pass, and band-pass first-order RC filters. Find cutoff frequency and attenuation at any target frequency.
Low-Pass RC Filter
$$f_c = \dfrac{1}{2\pi RC} \qquad |H(f)| = \dfrac{1}{\sqrt{1+(f/f_c)^2}}$$
Optional: check attenuation at a specific frequency
โ Please enter valid R and C values.
๐ก At fc the output is attenuated by โ3 dB (โ 70.7% of input). Each octave above fc adds another โ6 dB roll-off (โ20 dB/decade).
Attenuation vs. Frequency (Low-Pass)
| Freq / fc | Frequency | Gain (V/V) | Attenuation (dB) | Pass |
|---|
High-Pass RC Filter
$$f_c = \dfrac{1}{2\pi RC} \qquad |H(f)| = \dfrac{f/f_c}{\sqrt{1+(f/f_c)^2}}$$
Optional: check attenuation at a specific frequency
โ Please enter valid R and C values.
๐ก At fc the output is โ3 dB. Each octave below fc adds another โ6 dB (โ20 dB/decade roll-off in the stop-band).
Attenuation vs. Frequency (High-Pass)
| Freq / fc | Frequency | Gain (V/V) | Attenuation (dB) | Pass |
|---|
Band-Pass Filter (HP + LP stages)
$$f_L = \dfrac{1}{2\pi R_{HP}C_{HP}} \qquad f_H = \dfrac{1}{2\pi R_{LP}C_{LP}}$$
High-Pass stage (sets lower cutoff fL):
Low-Pass stage (sets upper cutoff fH):
โ Please enter valid values and ensure fL < fH.
๐ก For a non-interacting design, use RLP < RHP / 10 so the LP stage doesn't load the HP stage significantly.