1. Active power (P, unit: watts, W) is the actual electrical power consumed on the load, used for useful work and directly involved in energy conversion. For example, an electric motor converts electrical energy into mechanical energy, and a light bulb converts electrical energy into light energy, providing the energy required for electrical equipment such as motors, heaters, lighting equipment, etc.
2. Reactive power (Q, unit: reactive, VAR) refers to the periodic energy exchange between reactive elements (such as inductors and capacitors) and the power source in an AC circuit. It does not perform useful work, but supports energy storage for magnetic or electric fields. Reactive power is used to establish and maintain magnetic or electric fields, rather than directly doing work. It supports the normal operation of equipment such as transformers and motors, ensuring that these devices can effectively generate and transmit electromagnetic fields.