Question

The function of Q-meter is to measure

• A. Capacitance
• B. Inductance
• C. Quality factor of capacitor and inductor
• D. Quality factor and form factor of capacitor and inductor

Hint:

Higher Q ⇒ lower energy loss.

Answer 1

The Correct Option is C

Step 1: Explain how Q-meter uses resonance.
A Q-meter connects the unknown inductor (or capacitor) into a series resonant circuit with a calibrated variable capacitor. The circuit is tuned to resonance by adjusting the capacitor until the output voltage across it peaks.

Step 2: Use voltage magnification at resonance.
At series resonance, the voltage across the capacitor is $V_C = Q \times V_{applied}$. By measuring the ratio $V_C / V_{applied}$, the meter directly reads the Q value.

Step 3: State what is measured.
The Q-factor $= X/R$ for an inductor or $= 1/(\omega C R)$ for a capacitor. The Q-meter measures the quality factor for both inductors and capacitors. \[ \boxed{\text{Quality factor of capacitor and inductor}} \]