Question

Discuss ‘resonance’ in a series LCR circuit and write the expression for resonant frequency.

Answer 1

Resonance in a series LCR circuit occurs when the inductive reactance and capacitive reactance cancel each other, i.e.,

X_L = X_C

ωL = `1/(omega C)`

So, resonant frequency,

ω₀ = `1/(sqrt(L C))`

Resonant frequency in Hertz is,

f₀ = `1/(2 pi sqrt(L C))`

At resonance, Z = R, i.e., the circuit is purely resistive, and the current is maximum.