LC Resonance Calculator
Find resonant frequency, or solve for the missing L or C component value.
Resonant frequency
5.03 kHz
Wavelength: 59.6 km
Formula
f₀ = 1 / (2π·√(L·C))
At f₀ an LC tank exchanges energy between the inductor and capacitor.
LC resonance
An inductor and capacitor together form a resonant 'tank' that naturally oscillates at one frequency, f₀. Near that frequency the circuit's response peaks sharply, as the bell curve above shows.
Switch modes to solve for the inductor or capacitor you need to land on a target frequency.
Design notes
- Resonant frequency depends on the product L·C — many L/C combinations give the same f₀.
- Higher L relative to C raises the impedance at resonance; the trade-off affects bandwidth and 'Q'.
- Parasitic resistance and component tolerance shift the real peak from the ideal calculation.
Where it's used
Radio tuning, RF matching networks, oscillators, EMI/notch filters, and wireless-power and antenna circuits.
Frequently Asked Questions
What is LC resonance?+
At resonance, the inductive reactance (XL = 2πfL) equals the capacitive reactance (XC = 1/(2πfC)), and energy oscillates between the inductor and capacitor. Resonant frequency f = 1 / (2π√(LC)).
Where is LC resonance used?+
Radio receivers (tuning circuits), RF amplifiers, oscillators, band-pass/stop filters, and impedance matching networks all rely on LC resonance.