AC Voltage Across Resonant LCRHardQuestion 20206
Question
At resonance in a series LCR circuit, voltage across L and C individually can be:
- AEqual to supply voltage
- BGreater than supply voltage by factor QCorrect
- CLess than supply voltage
- DZero
Correct answer
Greater than supply voltage by factor Q
Explanation
At resonance, V_L = QV (voltage across inductor) and V_C = QV (across capacitor), where V is the supply RMS voltage and Q is the quality factor. V_L and V_C are equal and opposite, so they cancel in the loop — the net voltage across them is zero. But individually they can be Q times the supply — this is voltage magnification.