EASA / CAR Part-66 · Module 3 · 3.14 R, C and L Circuits · Cat B1/B2

Series LC Resonance

At the resonant frequency, XL and XC cancel, impedance is at a minimum and current peaks. Change L, C and the damping R and watch the resonance curve shift and sharpen.

Resonant f₀
,
Peak current
,
Q factor
,
Bandwidth
,

f₀ = 1 ÷ (2π√(LC)). A lower R gives a taller, sharper peak, a higher quality factor Q = (1/R)√(L/C), and a narrower bandwidth. This selectivity is how radios tune to one station.