Filters Formulas
Filter formulas set the cutoff frequency, bandwidth, and selectivity of passive and active filters. These calculators turn component values into frequency response so you can shape signals precisely. They are fundamental to audio, sensor conditioning, and noise rejection.
Filters Formula Calculators
- RC Low-Pass Filter fc = 1 / (2πRC)
- RC High-Pass Filter fc = 1 / (2πRC)
- Bandpass Bandwidth BW = f2 − f1
- Filter Rolloff Rate Rolloff = N × 20 dB/decade
- Notch Frequency f = 1 / (2π√(LC))
- Butterworth Q Factor Q = 1 / (2 × sin(π/(2N)))
- Sallen-Key Cutoff Frequency fc = 1 / (2π × √(R1×R2×C1×C2))
- Chebyshev Filter Order N = acosh(√(ε²s/ε²p)) / acosh(fs/fp)
- Bessel Filter Group Delay τ = R × C
- Active Filter Gain (MFB) Gain = −Rf / Ri
- Filter Q to Damping Ratio Q = 1 / (2 × ζ)
- LC Filter Cutoff Frequency fc = 1 / (2π × √(L × C))
- First-Order Bode Phase φ = −arctan(f/fc)
- Moving Average Filter Bandwidth f3dB ≈ 0.443 × fs / N
- Switched-Capacitor Filter Cutoff fc = fclk / ratio
- Pi-Filter Attenuation A = 20 × log10(1/(ω² × L × C))
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