### Q Factor and Bandwidth of a Resonant Circuit

Textbook
- Vol. II - Alternating Current (AC) - Chapter 6 - Resonance

The Q, or quality, factor of a resonant circuit is a measure of the “goodness” or quality of a resonant circuit. A higher value for this figure of merit corresponds to a more narrow bandwith, which is desirable in many applications. More formally, Q is the ratio of power stored to power dissipated in the circuit reactance and resistance, respectively:
Q = Pstored/Pdissipated = I2X/I2R Q = X/R