In a series RLC circuit fed from an AC source, the amplitude of t
| In a series RLC circuit fed from an AC source, the amplitude of the voltage across the resistor is 120 V and the amplitude of the voltages across the capacitor and inductor is 50 V each at resonance. What is the amplitude of the source voltage?
A. 80 V
B. 120 V
C. 170 V
D. 220 V
Please scroll down to see the correct answer and solution guide.
Right Answer is: B
SOLUTION
Concept:
For a series RLC circuit, as shown, the net magnitude/amplitude of the source voltage is given by:
\(V_{net}=\sqrt{V_R^2+(V_L-V_C)^2}\)
VR = Voltage across the resistor
VL = Voltage across the inductor
VC = Voltage across the capacitor
Analysis:
At resonance, the net impedance is purely resistive resulting in VL = VC
This is explained as shown:
Given VL = VC = 50 V
VR = 120 V
The net amplitude/magnitude of the source voltage is given by:
\(V_{net}=\sqrt{V_R^2+(V_L-V_L)^2}\)
\(V_{net}=\sqrt{V_R^2}=V_R=120~V\)
