What is the primary difference between real power and reactive power in AC circuits?

The primary difference between real power and reactive power in AC circuits lies in their definitions and roles in performing work within the circuit. Real power, measured in watts (W), represents the power that is actually consumed and used to perform useful work, such as lighting a bulb or powering a motor. This power is what does the meaningful work in an electrical system.

On the other hand, reactive power, measured in volt-amperes reactive (VAR), does not perform useful work in the same sense; instead, it oscillates between the source and the load. It is crucial for maintaining the voltage levels necessary for the proper functioning of inductive and capacitive elements in the system, but it does not contribute to net energy consumption or tangible work output.

This distinction is vital for understanding power factor calculations and the efficiency of AC circuits, as real power and reactive power together influence how effectively electrical systems operate.