What is electrical power?

We know of active and reactive power from text books and other sources. But the basic concept to electric power and its constitutes are most of the time misleading and vague as these are some virtual terms. After studying and searching through internet I have gathered some concept on electrical power- active, reactive power, apparent power.

Electrical power

In simple word we can define electrical power as the multiplication of voltage and current at any instant. We know P=V*I, Power= voltage*current. But this needs some extended information. 

Power in Direct Current (DC) circuit
In case of Direct Current, the voltage and current level are always constant.
So power = voltage x current.

Power in Alternating Current (AC) circuit

In case of Alternating current with inductive and capacitive load this electrical power is called apparent power. As in this case the electrical power is divided in to two parts active power and reactive power.

                                  Fig: Blinking of AC Lighting captured by high-powered camera. 

                                                            Light is emitted twice each cycle.

Thus with Alternating Current, Apparent Power = RMS value of Voltage x RMS value of current. [RMS - root mean square].