Low Pass Filter Simulator
Simulate RC cutoff frequency, gain, and phase response
Low-Pass Filter Formulas
| Cutoff frequency | fc = 1 / (2piRC) |
| Magnitude | |H(f)| = 1 / sqrt(1 + (f/fc)^2) |
| Gain in dB | 20 log10(|H(f)|) |
| Phase | phase = -atan(f/fc) |
Step-by-Step Example
For R = 1000 ohm and C = 0.1 uF, convert C to 0.0000001 F. The cutoff frequency is fc = 1 / (2pi x 1000 x 0.0000001), which is about 1591.55 Hz. At this frequency the output is about 70.7% of the input.
Where Low-Pass Filters Are Used
- Smoothing noisy sensor readings.
- Reducing high-frequency noise before analog-to-digital conversion.
- Audio tone shaping and simple signal conditioning.
- Creating slow voltage changes from fast switching signals.
Frequently Asked Questions
What is a low-pass filter?▼
A low-pass filter passes low-frequency signals more easily and attenuates high-frequency signals.
What is the RC cutoff frequency?▼
For a simple RC low-pass filter, cutoff frequency is fc = 1 / (2 pi R C).
What happens at cutoff frequency?▼
At cutoff frequency, the output magnitude is about 0.707 of the input, or -3 dB.
What does increasing capacitance do?▼
Increasing capacitance lowers the cutoff frequency, so the filter attenuates high frequencies earlier.
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