Calculate the resonant frequency of an LC or RLC circuit and the component values to tune it.
Resonant frequency depends on the product of L and C, so many combinations give the same frequency. The characteristic impedance √(L/C) distinguishes them and determines the current and voltage levels at resonance. Choosing L and C to hit a frequency is underdetermined, so the second constraint is usually the impedance the circuit must present.
Resonant Frequency RLC
f₀ = 1 ÷ (2π√(LC)); rearranged, C = 1 ÷ ((2πf₀)² L)
f₀ = 1 ÷ (2π√(LC)); rearranged, C = 1 ÷ ((2πf₀)² L) Resonant frequency depends on the product of L and C, so many combinations give the same frequency. The characteristic impedance √(L/C) distinguishes them and determines the current and voltage levels at resonance.
Choosing L and C to hit a frequency is underdetermined, so the second constraint is usually the impedance the circuit must present.
This calculator takes 3 inputs: Inductance, Capacitance, Target resonant frequency. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.