MAXScanner electronics calculator
Updated 2026-09-16
RC Filter Calculator — Cutoff, Gain, Phase & Time Constant
Analyze an ideal first-order RC low-pass or high-pass response from resistance, capacitance and signal frequency with engineering-unit inputs.
Inputs
Results
Cutoff 1,591.549 Hz
Gain 0.846733
Gain -1.44507 dB
Phase -32.14191°
τ 0.0001 s
More actions
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Your calculation, step by step
- 1.C = 100 nF = 0.0000001 F; Cutoff: fc = 1 ÷ (2πRC) = 1,591.549 Hz.
- 2.f/fc = 1,000 ÷ 1,591.549 = 0.6283185; Low-pass.
Formula, example and limits
fc=1/(2πRC); LP |H|=1/√(1+(f/fc)²); HP |H|=(f/fc)/√(1+(f/fc)²).
1 kΩ and 100 nF gives fc ≈ 1.592 kHz.
- Ideal first-order passive RC network.
- Source and load impedance are not included.
Frequently asked questions
Is cutoff always -3 dB?
For the ideal first-order response, magnitude at cutoff is 1/√2, about -3.01 dB.
How is this different from RC time constant?
The same RC product sets both τ=RC and fc=1/(2πτ).