Power Triangle is the representation of a right angle triangle showing the relation between active the power, reactive power and apparent power. When each component of the current that is the active component (Icosϕ) or the reactive component (Isinϕ) is then multiplied by the voltage V, a power triangle is obtained shown in the figure below

The power which is actually consumed or utilized in an AC Circuit is called True power or Active Power or real power. It is measured in kilowatt (kW) or MW. The power which flows back and forth that means it moves in both the direction in the circuit or reacts upon it, is called Reactive Power. The reactive power is measured in kilovolt-ampere reactive (kVAR) or MVAR. The product of root means square (RMS) value of voltage and current is known as Apparent Power. This power is measured in KVA or MVA.

The following point shows the relationship between the following quantities and is explained by graphical representation called Power Triangle shown above.

- When an active component of current is multiplied by the circuit voltage V, it results in active power.it is this power which produces torque in the motor, heat in the heater, etc. This power is measured by the wattmeter.
- When the reactive component of the current is multiplied by the circuit voltage, it gives reactive power. This power determines the power factor, and it flows back and froths in the circuit.
- When the circuit current is multiplied by the circuit voltage, it results in the apparent power.
- From the power triangle shown above the power, the factor may be determined by taking the ratio of true power to the apparent power.

As we know simply power means the product of voltage and current but in AC circuit except for pure resistive circuit, there is usually a phase difference between voltage and current and thus VI does not give real or true power in the circuit.