What does true power represent in an AC circuit?

True power, represented in watts (W), signifies the actual power that is available to perform useful work in an AC circuit. It is the component of power that is effectively converted into mechanical energy, heat, or light, depending on the application. True power accounts for the phase difference between voltage and current; it reflects the energy consumed by resistive components in the circuit, as opposed to energy that is stored or returned to the source, which is represented by reactive power.

In contrast, total power consumed includes a combination of both active (true) power and reactive power. Reactive power, on the other hand, is associated with energy storage in inductors and capacitors and does not equate to useful work done. Apparent power combines both true power and reactive power and is measured in volt-amperes (VA). Thus, true power is distinct in that it directly correlates with the useful output of the circuit, making it a critical concept in understanding AC power systems.