LC Resonance Calculator
Calculate resonant frequency, angular frequency, Q-factor, and bandwidth for series or parallel LC/LCR circuits.
Input Parameters
Results
Resonant Frequency (f0)—
Angular Frequency (ω0)—
Characteristic Impedance (Z0)—
Quality Factor (Q)—
Bandwidth (BW)—
Damping Ratio (ζ)—
💡 Usage & Formula
LC Resonance occurs when inductive and capacitive reactances cancel each other out, making the circuit act as a bandpass or bandstop filter.
Formulas:
- Resonant Frequency:
f0 = 1 / (2 * pi * sqrt(L * C)) - Series Quality Factor:
Q = sqrt(L / C) / R - Parallel Quality Factor:
Q = R * sqrt(C / L)
Usage: Enter your Inductance (L) and Capacitance (C) to find the resonance point and characteristic impedance.
When you need it: Finding the resonant frequency of an LC tank for a filter, oscillator or matching network, plus its characteristic impedance for setting the loaded Q.
Worked example: L = 10 µH, C = 100 pF → f = 1 / (2π√(LC)) ≈ 5.03 MHz. The characteristic impedance is Z0 = √(L/C) = √(1e5) ≈ 316 Ω.
Tips & gotchas:
- Frequency scales as
1/√(LC)— to halve it, quadruple either L or C. - Loaded Q sets bandwidth:
BW = f / Q, so a high-Q tank is narrow and sharp. - Stray board capacitance and lead inductance shift the real resonance — expect to trim in hardware.
- Use NP0/C0G capacitors for a stable, low-drift tank; class-2 dielectrics move with temperature and bias.
📖 References:
LC circuit (Wikipedia)