What is meant by Q-meter

Q-meter is generally used to measure the Q-factor of the coil.

The Q-meter is an instrument designed for measurement of Q-factor of a coil as well as for the measurement of electrical properties of coils and capacitors.

The Q-meter operates on the principle of series resonance i.e, under resonant condition of an acseries, circuit voltage across the capacitor is equal to the applied voltage times of Q of the circuit.