**(1)**

**Real Power: (P)**

Alternative words used for Real Power (Actual Power, True Power, Watt-full Power, Useful Power, Real Power, and Active Power)

In a DC Circuit, power supply to the DC load is simply the product of Voltage across the load and Current flowing through it i.e., P = V I. because in DC Circuits, there is no concept of phase angle between current and voltage. In other words, there is no Power factor in DC Circuits.

But the situation is Sinusoidal or AC Circuits is more complex because of phase difference between Current and Voltage. Therefore average value of power (Real Power) is P = VI Cosθ is in fact supplied to the load.

In AC circuits, When circuit is pure resistive, then the same formula used for power as used in DC as P = V I.

You may also read about Power Formulas in DC, AC Single Phase and and AC Three Phase Circuits.

**Real Power formulas:**

P = V I (In DC circuits)

P = VI Cosθ (in Single phase AC Circuits)

P = √3 V

_{L}I_{L}Cosθ or (in Three Phase AC Circuits)P = 3 V

_{Ph}I_{Ph}CosθP = √ (S

^{2}– Q^{2})^{or}P =√ (VA

^{2 }– VAR^{2}) or^{ }Real or True power = √ (Apparent Power

^{2}– Reactive Power^{2}) orkW = √ (kVA

^{2}– kVAR^{2})**(2) Reactive Power: (Q)**

Also known as (Use-less Power, Watt less Power)

The powers that continuously bounce back and forth between source and load is known as reactive Power (Q)

Power merely absorbed and returned in load due to its reactive properties is referred to as reactive power

The unit of Active or Real power is Watt where 1W = 1V x 1 A.

Reactive power represent that the energy is first stored and then released in the form of magnetic field or electrostatic field in case of inductor and capacitor respectively.

Reactive power is given by Q = V I Sinθ which can be positive (+ve) for inductive, negative (-Ve) for capacitive load.

The unit of reactive power is Volt-Ampere reactive. I.e. VAR where 1 VAR = 1V x 1A.

In more simple words, in Inductor or Capacitor, how much magnetic or electric field made by 1A x 1V is called the unit of reactive power.

**Reactive power formulas:**

Q = V I Sinθ

Reactive Power

^{ }=√ (Apparent Power^{2}- True power^{2})VAR =√ (VA

^{2 }– P^{2})kVAR = √ (kVA

^{2}– kW^{2})**(3) Apparent Power: (S)**

The product of voltage and current if and only if the phase angle differences between current and voltage are ignored.

Total power in an AC circuit, both dissipated and absorbed/returned is referred to as apparent power

The combination of reactive power and true power is called apparent power

In an AC circuit, the product of the r.m.s voltage and the r.m.s current is called

*apparent power*.It is the product of Voltage and Current without phase angle

The unit of Apparent power (S) VA i.e. 1VA = 1V x 1A.

When the circuit is pure resistive, then apparent power is equal to real or true power, but in inductive or capacitive circuit, (when Reactances exist) then apparent power is greater than real or true power.

**Apparent power formulas:**

S = V I

Apparent Power = √ (True power

^{2}+ Reactive Power^{2})kVA = √kW

^{2}+ kVAR^{2}

**AlsoNote that;**Resistor absorbs the real power and dissipates in the form of heat and light.

Inductor absorbs the reactive power and dissipates in the form of magnetic field

Capacitor absorbs the reactive power and dissipates in the form of electric or electrostatic filed

**∴**These all quantities trigonometrically related to each other as shown in below figure.

*Click image to enlarge*

For more Clearance and explanation., i used Lays Chips and Beer Analogy for Real or True Power, Reactive Power , Apparent power and power factor

*Lays Chips Analogy of Real or True Power, Reactive Power, Apparent power & power factor**Click image to enlarge*

* Beer Analogy of Active or True power, Reactive power, Apparent Power and Power factor. *

You may also read about

- Power Factor
- Causes of low Power Factor
- Disadvantages of Low Power Factor
- Power Factor improvement Methods with Their advantages & Disadvantages
- Advantages of Power factor improvement and Correction
- How to Calculate the Suitable Capacitor Size in Farads & kVAR for Power factor Improvement (Easiest way ever)
- How to Convert Capacitor Farads into kVAR and Vice Versa (For Power factor improvement)

The analogy with the beers and the chips are simply awesome!!!! specially the one with the beers. Can I use the beer image for one of my presentations? how can I get this image? thanks in advance.<br />

You are Welcome dear

Awesome

The beer and chip diagrams are deceptive. They imply True Power and Reactive Power when added together are Apparent Power. It does not. It is the the square of true power and the square of reactive power which equals the square of apparent power.

Actually u people made electrical is very easy…hatsoff to all ur people efforts…once upon a time i was very confused about this subject..but by d grace of allah nw all my confusion was gone…if i go good position in my carrier one of d credit goes to u people also..thanks a lot..keep it up..

No this is very simple farmula but using to mind so all heard also question simple but some solution these are hord, I can do this question but all people some many help me…?