The Quality Factor ($Q$) describes the 'sharpness' of resonance in an RLC circuit. $Q=\frac{{\omega }_{0}L}{R}=\frac{1}{{\omega }_{0}CR}=\frac{1}{R}\sqrt{\frac{L}{C}}$

• High Q: Low resistance / damping. The peak current at resonance is very high, and the 'bandwidth' (the range of frequencies where current is significant) is very narrow.
• This makes the circuit highly selective, which is desirable for radio tuning.