RLC Circuit Calculator
Calculate the resonant frequency, quality factor, and bandwidth of a series RLC circuit.
Results are theoretical values for an ideal series RLC circuit. Real components have parasitic resistance, tolerance variations, and temperature drift — verify with measurement for critical designs.
How it works
- 1Enter the resistance (Ω), inductance (mH), and capacitance (µF) of the series RLC circuit.
- 2The calculator applies f₀ = 1/(2π√(LC)) and Q = (1/R)√(L/C).
- 3Read the resonant frequency in Hz and kHz, the Q factor, and the −3 dB bandwidth (f₀/Q).
Use cases
- Designing tuned radio-frequency filters and antenna matching networks.
- Selecting components for oscillator circuits and signal generators.
- Analysing the selectivity and bandwidth of bandpass filter stages.
Frequently asked questions
What is the resonant frequency of an RLC circuit?
f₀ = 1/(2π√(LC)) is the frequency where inductive and capacitive reactances cancel. With L = 100 mH and C = 1 µF, f₀ ≈ 503 Hz.
What does the quality factor Q tell me?
Q = (1/R)√(L/C) measures selectivity. A high Q (>10) passes a narrow band; a low Q gives a wide, lossy response. Lower resistance raises Q.
How is bandwidth related to Q?
The −3 dB bandwidth is BW = f₀/Q. A 1 kHz resonance with Q = 10 has a 100 Hz bandwidth.
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