What does a unity power factor indicate about voltage and current?

A unity power factor indicates that the voltage and current waveforms in an electrical circuit are in phase with one another. This means that the peak values of voltage and current occur at the same time, resulting in the most efficient use of electrical power. When voltage and current are in phase, it maximizes the transfer of power to the load, as there is no reactive power being present in the system.

In practical terms, a unity power factor of 1.0 signifies that all the power supplied by the source is being effectively converted into useful work. This occurs in purely resistive circuits, where the impedance is purely resistive, and does not include reactive components like inductance or capacitance that could cause the current and voltage to be out of phase.