RC Filter Calculator

Interactive Bode plot — visualize magnitude and phase response in real time.

Component Values

Results

Cutoff Frequency (f₀)1.592 kHz
Angular Freq. (ω₀)1.000e+4 rad/s
Time Constant (τ)100 µs
Magnitude at f₀-3.01 dB
Phase at f₀-45°
Vin10 kΩVout10 nF

RC Low-Pass Filter

Bode Plot

How does a Low-Pass RC Filter work?

A low-pass filter passes frequencies below the cutoff frequency f₀ and attenuates higher frequencies. At DC (f = 0), the capacitor is an open circuit and all voltage appears at the output. At very high frequencies, the capacitor short-circuits the output to ground.

Transfer Function

H(jω) = 1 / (1 + jωRC)

Cutoff Frequency

f₀ = 1 / (2π · R · C)

Key Points

  • At f = f₀: output is −3 dB (≈ 70.7% of input amplitude)
  • Phase at f₀: −45°
  • Roll-off rate: −20 dB/decade above f₀
  • Time constant τ = RC determines the response speed

Applications

  • Audio tone controls (bass boost)
  • Anti-aliasing before ADC sampling
  • Power supply ripple filtering
  • Signal smoothing and averaging