Problem 4.132

Demonstrate that at low damping the quality factor $Q$ of a circuit maintaining forced oscillations is approximately equal to $\omega_{0} / \Delta \omega,$ where $\omega_{0}$ is the natural oscillation frequency, $\Delta \omega$ is the width of the resonance curve $I(\omega)$ at the "height" which is $\sqrt{2}$ times less than the resonance current amplitude.