Which one of the phasor diagrams shown below best represents a series LRC circuit driven at resonance?
A) 1
B) 2
C) 3
D) 4
E) 5

Question

Which one of the phasor diagrams shown below best represents a series LRC circuit driven at resonance? 
A) 1 
B) 2 
C) 3 
D) 4 
E) 5

Quizplus · Accepted Answer

At resonance, the reactance of capacitor and inductor cancel each other out, resulting in an impedance that is purely resistive (i.e., the circuit becomes purely resistive at resonance). This means that the phase angle between voltage and current is 0 degrees, as shown in diagram C, where the current and voltage phasors are in phase. In other diagrams, the phase angle is not 0 degrees, indicating that the circuit is not at resonance.

Which One of the Phasor Diagrams Shown Below Best Represents