What does the power factor measure in an electrical circuit?

The power factor measures the ratio of useful power to total power in an electrical circuit, making it a crucial aspect of assessing how efficiently electrical energy is being utilized. In alternating current (AC) systems, power can be categorized into two types: active power (or real power), which does useful work, and reactive power, which does not contribute to output but is necessary for maintaining voltage levels. The power factor quantifies the proportion of power that performs actual work compared to the total power being drawn from the source.

A power factor of 1 (or 100%) indicates that all the power is being effectively used for work, whereas a lower power factor signifies that a portion of the power is wasted or not effectively converted into useful work. This is particularly important in commercial and industrial applications, where low power factors can lead to higher costs and inefficiencies. Therefore, understanding the power factor is essential for optimizing electrical systems and ensuring energy efficiency.