What component is used for improving power factor in electrical systems?

A capacitor is employed in electrical systems to improve power factor, which is a measure of how effectively electrical power is being converted into useful work output. A low power factor indicates that more current is required to deliver the same amount of power, leading to increased energy losses and reduced efficiency.

The primary function of a capacitor in this context is to provide reactive power. When capacitors are connected to an electrical system, they can compensate for the inductive loads (like motors and transformers) which typically cause the power factor to lag. By introducing leading reactive power, capacitors help bring the overall power factor closer to unity (1.0), thereby improving the efficiency of the power system.

Transformers, while essential components in electrical systems, do not specifically improve power factor; they primarily serve to change voltage levels. Resistors dissipate energy as heat and do not provide reactive power, thus not contributing to power factor correction. Inductors, on the other hand, produce lagging reactive power and can worsen the power factor when connected, making them counterproductive in this specific application.