What effect does a capacitor have on AC voltage and current?

Capacitors play a significant role in AC circuits by introducing a phase shift between the voltage and current. This phase shift occurs because a capacitor stores energy in the form of an electric field when voltage is applied. In an AC circuit, this means that the current can either lead or lag behind the voltage, depending on the specific configuration of the circuit.

When a capacitor is connected to an AC voltage source, it causes the current to oscillate ahead of the voltage wave. This leading effect is critical in reactive power management within electrical systems, particularly in applications where maintaining power factor is essential. A better understanding of this relationship is important for those involved in servicing electrical equipment, as it impacts the overall efficiency and functionality of inductive and capacitive components.

The other choices do not accurately represent the relationship between AC voltage and current regarding capacitors. For example, while it may seem logical to believe that a capacitor increases voltage and current, this is not the case; instead, it influences how they interact. Similarly, a capacitor does not reduce frequency nor has no effect—its primary role is to manage the timing of voltage and current through phase shifts.