# Moby Thesaurus

amperage, armipotence, authority, beef, black power, brute force, charge, charisma, clout, cogence, cogency, compulsion, dint, drive, duress, effect, effectiveness, effectuality, electric horsepower, electric power, energy, flower power, force, force majeure, forcefulness, full blast, full force, hydroelectric power, hydroelectricity, influence, main force, main strength, mana, might, might and main, mightiness, moxie, muscle power, pizzazz, poop, potence, potency, potentiality, power, power load, power pack, power structure, power struggle, powerfulness, prepotency, productiveness, productivity, puissance, pull, punch, push, sinew, steam, strength, strong arm, superiority, superpower, validity, vehemence, vigor, vim, virility, virtue, virulence, vitality, watts, weight# English

## Noun

Electric power is defined as the rate at which
electrical
energy is transferred by an electric
circuit. The SI unit of power is the
watt.

When electric current flows in a circuit with
resistance,
it does work. Devices convert this work into many useful forms,
such as heat (electric
heaters), light
(light
bulbs), motion
(electric
motors) and sound
(loudspeaker).
Electricity can be produced by generation
or from storage
such as batteries.

# Mathematics of electric power

## In circuits

Electric power, like mechanical power, is represented by the letter P in electrical equations. The term wattage is used colloquially to mean "electric power in watts."In direct current resistive
circuits, instantaneous electrical power is calculated using
Joule's
Law, which is named after the British physicist James Joule,
who first showed that heat and mechanical energy were
interchangeable. P = V I \,

where

For example: 2\,\mbox \cdot 12\,\mbox = 24\,\mbox
\, .

Joule's law can be combined with Ohm's law to
produce two more equations: P = I^2 R\, = \frac \,

where

- R is the resistance (Ohm or Ω).

For example: (2\,\mbox)^2 \cdot 6\,\Omega =
24\,\mbox \,

and \frac = 24\,\mbox \,

In alternating
current circuits, energy storage elements such as inductance and capacitance may result in
periodic reversals of the direction of energy flow. The portion of
power flow that, averaged over a complete cycle of the AC waveform,
results in net transfer of energy in one direction is known as
real
power (also referred to as active power). That portion of power
flow due to stored energy, that returns to the source in each
cycle, is known as reactive
power.

The relationship between real power, reactive
power and apparent power can be expressed by representing the
quantities as vectors. Real power is represented as a horizontal
vector and reactive power is represented as a vertical vector. The
apparent power vector is the hypotenuse of a right triangle formed
by connecting the real and reactive power vectors. This
representation is often called the power triangle. Using the
Pythagorean
Theorem, the relationship among real, reactive and apparent
power is:

- \mbox^2 = \mbox^2 + \mbox^2

Real and reactive powers can also be calculated
directly from the apparent power, when the current and voltage are
both sinusoids with a
known phase angle between them:

- \mbox = \mbox * cos \mbox

- \mbox = \mbox * sin \mbox

The ratio of real power to apparent power is
called power factor
and is a number always between 0 and 1.

## In space

Electrical power flows wherever electric and magnetic fields exist in the same place. The simplest example of this is in electrical circuits, as the preceding section showed. In the general case, however, the simple equation P=IV must be replaced by a more complex calculation, the integral of the vector cross-product of the electrical and magnetic fields over a specified area, thus: \mathbf = \int_S \mathbf \times \mathbf \cdot \mathbf. \,The result is a scalar since it is the surface
integral of the Poynting
vector.

# See also

portal Energy## Power generation

# References

# External links

wattage in Afrikaans: Elektriese drywing

wattage in Czech: Elektrický výkon

wattage in Danish: Effekt
(fysik)#Effekt_i_elektriske_kredsl.C3.B8b

wattage in German: Elektrische Leistung

wattage in Estonian:
Võimsus#V.C3.B5imsus_elektrotehnikas

wattage in Spanish: Potencia eléctrica

wattage in French: Puissance
(physique)#En_.C3.A9lectricit.C3.A9

wattage in Galician: Enerxía eléctrica

wattage in Korean: 전력

wattage in Indonesian: Daya listrik

wattage in Inuktitut:
ᑲᑉᐳᑎᒨᖅᑐᖅ/kapputimuuqtuq

wattage in Italian: Potenza
(elettrotecnica)

wattage in Hebrew: הספק חשמלי

wattage in Japanese: 電力

wattage in Portuguese: Potência elétrica

wattage in Russian: Электрическая мощность

wattage in Simple English: Electric power

wattage in Slovenian: Električna energija

wattage in Swedish:
Effekt#F.C3.B6r_likstr.C3.B6m_.28DC.29_och_sp.C3.A4nning

wattage in Tamil: மின்திறன்

wattage in Vietnamese: Điện lực

wattage in Chinese: 電源