What is active power (real power)?

Active power is measured in watts (W) and represents the rate at which energy is used or converted into other forms of energy, such as mechanical work, heat, or light. When a device consumes or delivers active power, it results in a load on the electrical system, leading to the transfer of energy from the source to the load.

In an alternating current (AC) electrical system, active power is the component of power that is in-phase with the voltage waveform. For example, in a resistive load, like an incandescent light bulb or an electric heater, the current flows in phase with the voltage, and the power consumed is purely active power. In this case, the electric energy supplied is entirely converted into heat or light, making it useful power.

The formula to calculate active power is:

Active Power (P) = Voltage (V) x Current (I) x Power Factor (PF)

Where:

Voltage (V) is the voltage across the load (measured in volts, V).

Current (I) is the current flowing through the load (measured in amperes, A).

Power Factor (PF) is a dimensionless value between 0 and 1 that represents the phase difference between the voltage and current waveforms. In purely resistive loads, the power factor is 1, while in reactive loads like inductors or capacitors, the power factor can be less than 1.

In summary, active power is the actual power consumed or supplied by an electrical device to perform useful work and is an important factor in designing and managing electrical systems efficiently.