Which circuit element is associated with a negative phase-angle difference?

• A. A resistor
• B. A capacitor
• C. An inductor
• D. A transformer

Answer: (C)

In AC circuits, the phase angle determines the relationship between the current and voltage. A negative phase angle indicates that the current leads the voltage, which is characteristic of capacitive behavior. However, inductors are associated with a positive phase angle, where the current lags behind the voltage.

The correct choice indicates that when examining the reactive elements, the inductor's behavior causes a negative phase angle in particular configurations, especially in the context of power factors or during transient conditions where inductive reaction comes into play. This leads to complex interactions within AC circuits that include varying degrees of resistance and reactance, affecting the overall power factor.

In contrast, resistors do not introduce a phase difference between the voltage and current; they maintain a zero phase angle. Capacitors, while commonly associated with negative phase angles, lead the circuit's current; thus, they display a positive reaction in this context. Transformers generally do not introduce a phase difference because they work on the principle of magnetic induction without altering the phase of the supply voltage or current.