Power triangle

                   Power triangle

The relationship among active power, reactive power and apparent power is illustrated by
a right angled triangle called the power triangle. Reactive power is the vertical axis of the triangle,
active power is the horizontal axis and apparent power or total power is the hypotenuse.
(Power triangle)

 Active Power:

When an active component of current is multiplied with circuit voltage, it results in active
or true power. This power produces torque in motors, heat in heaters, light in lamps etc., Further
wattmeter indicates this power.
(Active power)

 Reactive Power: 

When a reactive component of current is multiplied with circuit voltage, it results in
reactive power. This power flows back and forth without doing any work. This power determines
the power factor of the circuit.
(Reactive Power)

 Apparent Power: 

When the circuit current is multiplied with circuit voltage, it results in apparent power. i.e
product of voltage and current. In a.c circuit, there is phase difference between voltage and
current so that product of voltage and current does not give real power. To avoid confusion, it is
measured in volt-ampere.
(Apparent power)

Power Factor:

From power triangle, the power factor may also be determined by taking the ratio of
true power to apparent power.

                            True Power or Active Power
Power Factor =------------------------------------------------
                                     Apparant Power