By hvhipot 
Energy during RCL series resonance (or series resonance device)
set
then
indicate:
(1) The energy of inductance and capacitance varies sinusoidally, with a maximum value equal to WLm=WCm. The electric and magnetic field energy of L and C undergo periodic oscillation exchange, without exchanging energy with the power series resonance;
(2) The total energy is a constant that does not change over time. And equal to the maximum value
Q is a quantity that reflects the degree of electromagnetic oscillation in a series resonant circuit. The larger Q, the greater the total energy, and the less energy is consumed to maintain oscillation. The more intense the oscillation, the better the “quality” of the oscillating circuit. Generally, in circuits that require resonance, it is desirable to increase the Q value as much as possible.