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Alyson is the title individuals use to call me and I think it sounds fairly good when you say it. To perform lacross is the thing I adore most of all. Invoicing is what I do for a living but I've usually needed my personal business. I've usually loved residing in Alaska.<br><br>Feel free to visit my webpage - [http://myoceancounty.net/groups/apply-these-guidelines-when-gardening-and-grow/ psychics online]
[[File:Electricalgrid.jpg|thumb|Electric power is transmitted on [[Overhead power line|overhead lines]] like these, and also on underground [[high voltage cable]]s.]]
'''Electric power''' is the rate at which [[electric energy]] is transferred by an [[electric circuit]]. The [[SI]] unit of [[power (physics)|power]] is the [[watt (unit)|watt]], one [[joule]] per [[second]].
 
Electric power is usually produced by [[electric generator]]s, but can also be supplied by  sources such as [[electric batteries]]. Electric power is generally supplied to businesses and homes by the [[electric power industry]]. Electric power is usually sold by the [[kilowatt hour]] (3.6 MJ) which is the product of power in kilowatts multiplied by running time in hours.  Electric utilities measure power using an [[electricity meter]], which keeps a running total of the electric energy delivered to a customer.
 
==Definition==
Electric power, like [[power (physics)|mechanical power]], is the rate of doing [[work (electrical)|work]], measured in [[watt]]s, and represented by the letter ''P''. The term ''wattage'' is used colloquially to mean "electric power in watts."  The electric power in [[watt]]s produced by an electric current ''I'' consisting of a charge of ''Q'' coulombs every ''t'' seconds passing through an [[electric potential]] ([[voltage]]) difference of ''V'' is
:<math>P = \text{work done per unit time} = \frac {QV}{t} = IV \,</math>
where
:''Q'' is electric charge in [[coulomb]]s
:''t'' is time in seconds
:''I'' is electric current in [[ampere]]s
:''V'' is electric potential or voltage in [[volt]]s
 
 
==Explanation==
Electric power is transformed to other forms of power when [[electric charge]]s move through an [[electric potential]] ([[voltage]]) difference, which occurs in [[electrical component]]s in electric circuits.  When electric charges move through a potential difference from a high voltage to a low voltage, the energy in the potential is converted to [[kinetic energy]] of the charges, which perform work on the device.  Devices in which this occurs are called ''[[Passivity (engineering)|passive]]'' devices or ''loads''; they consume electric power, converting it to other forms such as [[mechanical work]], heat, light, etc. Examples are [[electrical appliance]]s, such as [[light bulb]]s, [[electric motor]]s, and [[electric heater]]s. 
 
If the charges are forced to move by an outside force in the direction from a lower potential to a higher, work is being done ''on'' the charges, so power is transferred to the electric current from some other type of energy, such as [[mechanical energy]] or [[chemical energy]].  Devices in which this occurs are called ''[[Passivity (engineering)|active]]'' devices or ''power sources''; sources of electric current, such as [[electric generator]]s and [[electric battery|batteries]].
 
===Passive sign convention===
{{main|Passive sign convention}}
In electronics, which deals with more passive than active devices, electric power consumed in a device is defined to have a positive sign, while power produced by a device is defined to have a negative sign.  This is called the ''[[passive sign convention]]''.
 
===Resistive circuits===
In the case of [[resistive]] (Ohmic, or linear) loads, Joule's law can be combined with [[Ohm's law]] (''V'' = ''I·R'') to produce alternative expressions for the dissipated power:
 
:<math>P = I^2 R = \frac{V^2}{R},</math>
 
where ''R'' is the [[electrical resistance]].
 
===Alternating current===
{{Main|AC power}}
In [[AC power|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 real power '''''P''''' in watts consumed by a device is given by
:<math>P = {1 \over 2}V_p I_p \cos \theta = V_{rms}I_{rms} \cos \theta \,</math>
where
:'''''V'''''<sub>p</sub> is the peak voltage in volts
:'''''I'''''<sub>p</sub> is the peak current in amperes
:'''''V'''''<sub>rms</sub> is the [[root-mean-square]] voltage in volts
:'''''I'''''<sub>rms</sub> is the [[root-mean-square]] current in amperes
:'''''θ''''' is the [[phase angle]] between the current and voltage sine waves
 
[[File:Power Triangle 01.svg|thumb|200px|Power triangle: The components of [[AC 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:
:<math>\mbox{(apparent power)}^2 = \mbox{(real power)}^2 + \mbox{(reactive power)}^2</math>
 
Real and reactive powers can also be calculated directly from the apparent power, when the current and voltage are both [[Sine wave|sinusoid]]s with a known phase angle θ between them:
 
:<math>\mbox{(real power)} = \mbox {(apparent power)}\cos(\theta)</math>
 
:<math>\mbox{(reactive power)} = \mbox {(apparent power)}\sin(\theta)</math>
 
The ratio of real power to apparent power is called [[power factor]] and is a number always between 0 and 1. Where the currents and voltages have non-sinusoidal forms, power factor is generalized to include the effects of distortion.
 
===Electromagnetic fields===
{{unreferenced section|date=November 2012}}
Electrical power flows wherever electric and magnetic fields exist together and fluctuate 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 [[cross product|cross-product]] of the electrical and magnetic field [[vector (geometric)|vectors]] over a specified area, thus:
:<math>
P = \int_S (\mathbf{E} \times \mathbf{H}) \cdot \mathbf{dA}. \,
</math>
 
The result is a scalar since it is the ''[[surface integral]]'' of the ''[[Poynting vector]]''.
 
==Electric power supply==
{{main|power supply}}
 
===Electricity generation===
{{main|electricity generation}}
The fundamental principles of electricity generation were discovered during the 1820s and early 1830s by the British scientist [[Michael Faraday]].  His basic method is still used today: electricity is generated by the movement of a loop of wire, or disc of copper between the poles of a [[magnet]].<ref>[http://www.theiet.org/about/libarc/archives/biographies/faraday.cfm 'The Institution of Engineering & Technology: Michael Faraday']</ref>
 
For [[electric utility|electric utilities]], it is the first process in the delivery of electricity to consumers. The other processes, electricity [[Electric power transmission|transmission]], [[Electric power distribution|distribution]], and electrical power storage and recovery using [[Pumped-storage hydroelectricity|pumped-storage]] methods are normally carried out by the [[electric power industry]].
 
Electricity is most often generated at a [[power station]] by electromechanical [[electrical generator|generators]], primarily driven by [[heat engine]]s fueled by chemical [[combustion]] or [[nuclear fission]] but also by other means such as the [[kinetic energy]] of flowing water and wind. There are many other technologies that can be and are used to generate electricity such as solar [[photovoltaics]] and [[geothermal power]].
 
===Battery power===
{{main|battery (electricity)}}
A '''battery''' is a device consisting of one or more [[electrochemical cell]]s that convert stored chemical [[energy]] into electrical energy.<ref name="Webster">[http://www.merriam-webster.com/dictionary/battery "battery" (def. 4b)], ''Merriam-Webster Online Dictionary'' (2009). Retrieved 25 May 2009.</ref> Since the invention of the first battery (or "[[voltaic pile]]") in 1800 by [[Alessandro Volta]] and especially since the technically improved [[Daniell cell]] in 1836, batteries have become a common power source for many household and industrial applications. According to a 2005 estimate, the worldwide battery industry generates [[United States dollar|US$]]48 [[1000000000 (number)|billion]] in sales each year,<ref>[http://www.dfj.com/cgi-bin/artman/publish/article_141.shtml Power Shift: DFJ on the lookout for more power source investments]. ''Draper Fisher Jurvetson''. Retrieved 20 November 2005.</ref> with 6% annual growth.
 
There are two types of batteries: [[Primary battery|primary batteries]] (disposable batteries), which are designed to be used once and discarded, and [[Secondary battery|secondary batteries]] (rechargeable batteries), which are designed to be recharged and used multiple times. Batteries come in many sizes, from miniature cells used to power [[hearing aid]]s and wristwatches to battery banks the size of rooms that provide standby power for [[telephone exchange]]s and computer [[data center]]s.
 
===Electric power industry===
{{main|electric power industry}}
The electric power industry provides the production and delivery of power, in sufficient quantities to areas that need [[electricity]], through a [[grid connection]]. The grid distributes electrical energy to customers. Electric power is generated by central [[power station]]s or by [[distributed generation]].
 
Many households and businesses need access to electricity, especially in [[developed nation]]s, the demand being scarcer in [[developing nation]]s. Demand for electricity is derived from the requirement for electricity in order to operate [[domestic appliance]]s, [[office equipment]], [[industry|industrial]] [[machinery]] and provide sufficient energy for both domestic and commercial lighting, heating, cooking and industrial processes. Because of this aspect of the industry, it is viewed as a [[public utility]] as [[infrastructure]].
 
==See also==
{{Portal|Energy}}
* [[High voltage cable]]
* [[EGRID]]
* [[Electric energy consumption]]
* [[Rural electrification]]
 
==Notes==
{{reflist}}
 
==References==
* [http://www.nerc.com/~filez/blackout.html Reports on August 2003 Blackout, North American Electric Reliability Council website]
* {{cite book
| last = Croft
| first = Terrell
| coauthors = Summers, Wilford I.
| title = American Electricians' Handbook
| url = http://books.mcgraw-hill.com/getbook.php?isbn=0071377352
| edition = Eleventh
| year = 1987
| publisher = McGraw Hill
| location = New York
| isbn = 0-07-013932-6
}}
* {{cite book
| last = Fink
| first = Donald G.
| authorlink = Donald G. Fink
| coauthors = Beaty, H. Wayne
| title = Standard Handbook for Electrical Engineers
| url = http://books.mcgraw-hill.com/getbook.php?isbn=0070220050
| edition = Eleventh
| year = 1978
| publisher = McGraw Hill
| location = New York
| isbn = 0-07-020974-X
}}
 
==External links==
* [http://www.energy.gov/energysources/electricpower.htm U.S. Department of Energy: Electric Power]
 
{{Electricity generation}}
 
[[Category:Electric power| ]]
[[Category:Electromagnetism]]
 
[[da:Effekt (fysik)#Effekt i elektriske kredsløb]]
[[et:Võimsus#Võimsus elektrotehnikas]]
[[sv:Effekt#För likström (DC) och spänning]]

Revision as of 14:31, 27 February 2013

Electric power is transmitted on overhead lines like these, and also on underground high voltage cables.

Electric power is the rate at which electric energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second.

Electric power is usually produced by electric generators, but can also be supplied by sources such as electric batteries. Electric power is generally supplied to businesses and homes by the electric power industry. Electric power is usually sold by the kilowatt hour (3.6 MJ) which is the product of power in kilowatts multiplied by running time in hours. Electric utilities measure power using an electricity meter, which keeps a running total of the electric energy delivered to a customer.

Definition

Electric power, like mechanical power, is the rate of doing work, measured in watts, and represented by the letter P. The term wattage is used colloquially to mean "electric power in watts." The electric power in watts produced by an electric current I consisting of a charge of Q coulombs every t seconds passing through an electric potential (voltage) difference of V is

where

Q is electric charge in coulombs
t is time in seconds
I is electric current in amperes
V is electric potential or voltage in volts


Explanation

Electric power is transformed to other forms of power when electric charges move through an electric potential (voltage) difference, which occurs in electrical components in electric circuits. When electric charges move through a potential difference from a high voltage to a low voltage, the energy in the potential is converted to kinetic energy of the charges, which perform work on the device. Devices in which this occurs are called passive devices or loads; they consume electric power, converting it to other forms such as mechanical work, heat, light, etc. Examples are electrical appliances, such as light bulbs, electric motors, and electric heaters.

If the charges are forced to move by an outside force in the direction from a lower potential to a higher, work is being done on the charges, so power is transferred to the electric current from some other type of energy, such as mechanical energy or chemical energy. Devices in which this occurs are called active devices or power sources; sources of electric current, such as electric generators and batteries.

Passive sign convention

Mining Engineer (Excluding Oil ) Truman from Alma, loves to spend time knotting, largest property developers in singapore developers in singapore and stamp collecting. Recently had a family visit to Urnes Stave Church. In electronics, which deals with more passive than active devices, electric power consumed in a device is defined to have a positive sign, while power produced by a device is defined to have a negative sign. This is called the passive sign convention.

Resistive circuits

In the case of resistive (Ohmic, or linear) loads, Joule's law can be combined with Ohm's law (V = I·R) to produce alternative expressions for the dissipated power:

where R is the electrical resistance.

Alternating current

Mining Engineer (Excluding Oil ) Truman from Alma, loves to spend time knotting, largest property developers in singapore developers in singapore and stamp collecting. Recently had a family visit to Urnes Stave Church. 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 real power P in watts consumed by a device is given by

where

Vp is the peak voltage in volts
Ip is the peak current in amperes
Vrms is the root-mean-square voltage in volts
Irms is the root-mean-square current in amperes
θ is the phase angle between the current and voltage sine waves
Power triangle: The components of AC 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:

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 θ between them:

The ratio of real power to apparent power is called power factor and is a number always between 0 and 1. Where the currents and voltages have non-sinusoidal forms, power factor is generalized to include the effects of distortion.

Electromagnetic fields

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This is one of the only things that require you to spend a little money to make money. Just go make an account, get a paypal account, and start selling. To go one step beyond just affiliating products and services is to create your own and sell it through your blog. Not great if you really enjoy trying out all the themes. Talking in real time having a real person causes it to be personal helping me personally to sort out how to proceed. The first step I took was search for a discount code, as I did with HostGator. Using a HostGator coupon is a beneficial method to get started. As long as the necessities are able to preserve the horizontal functionality of your site, you would pretty much be fine. Electrical power flows wherever electric and magnetic fields exist together and fluctuate 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 cross-product of the electrical and magnetic field vectors over a specified area, thus:

The result is a scalar since it is the surface integral of the Poynting vector.

Electric power supply

Mining Engineer (Excluding Oil ) Truman from Alma, loves to spend time knotting, largest property developers in singapore developers in singapore and stamp collecting. Recently had a family visit to Urnes Stave Church.

Electricity generation

Mining Engineer (Excluding Oil ) Truman from Alma, loves to spend time knotting, largest property developers in singapore developers in singapore and stamp collecting. Recently had a family visit to Urnes Stave Church. The fundamental principles of electricity generation were discovered during the 1820s and early 1830s by the British scientist Michael Faraday. His basic method is still used today: electricity is generated by the movement of a loop of wire, or disc of copper between the poles of a magnet.[1]

For electric utilities, it is the first process in the delivery of electricity to consumers. The other processes, electricity transmission, distribution, and electrical power storage and recovery using pumped-storage methods are normally carried out by the electric power industry.

Electricity is most often generated at a power station by electromechanical generators, primarily driven by heat engines fueled by chemical combustion or nuclear fission but also by other means such as the kinetic energy of flowing water and wind. There are many other technologies that can be and are used to generate electricity such as solar photovoltaics and geothermal power.

Battery power

Mining Engineer (Excluding Oil ) Truman from Alma, loves to spend time knotting, largest property developers in singapore developers in singapore and stamp collecting. Recently had a family visit to Urnes Stave Church. A battery is a device consisting of one or more electrochemical cells that convert stored chemical energy into electrical energy.[2] Since the invention of the first battery (or "voltaic pile") in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power source for many household and industrial applications. According to a 2005 estimate, the worldwide battery industry generates US$48 billion in sales each year,[3] with 6% annual growth.

There are two types of batteries: primary batteries (disposable batteries), which are designed to be used once and discarded, and secondary batteries (rechargeable batteries), which are designed to be recharged and used multiple times. Batteries come in many sizes, from miniature cells used to power hearing aids and wristwatches to battery banks the size of rooms that provide standby power for telephone exchanges and computer data centers.

Electric power industry

Mining Engineer (Excluding Oil ) Truman from Alma, loves to spend time knotting, largest property developers in singapore developers in singapore and stamp collecting. Recently had a family visit to Urnes Stave Church. The electric power industry provides the production and delivery of power, in sufficient quantities to areas that need electricity, through a grid connection. The grid distributes electrical energy to customers. Electric power is generated by central power stations or by distributed generation.

Many households and businesses need access to electricity, especially in developed nations, the demand being scarcer in developing nations. Demand for electricity is derived from the requirement for electricity in order to operate domestic appliances, office equipment, industrial machinery and provide sufficient energy for both domestic and commercial lighting, heating, cooking and industrial processes. Because of this aspect of the industry, it is viewed as a public utility as infrastructure.

See also

Sportspersons Hyslop from Nicolet, usually spends time with pastimes for example martial arts, property developers condominium in singapore singapore and hot rods. Maintains a trip site and has lots to write about after touring Gulf of Porto: Calanche of Piana.

Notes

43 year old Petroleum Engineer Harry from Deep River, usually spends time with hobbies and interests like renting movies, property developers in singapore new condominium and vehicle racing. Constantly enjoys going to destinations like Camino Real de Tierra Adentro.

References

External links

Template:Electricity generation

da:Effekt (fysik)#Effekt i elektriske kredsløb et:Võimsus#Võimsus elektrotehnikas sv:Effekt#För likström (DC) och spänning

  1. ↑ 'The Institution of Engineering & Technology: Michael Faraday'
  2. ↑ "battery" (def. 4b), Merriam-Webster Online Dictionary (2009). Retrieved 25 May 2009.
  3. ↑ Power Shift: DFJ on the lookout for more power source investments. Draper Fisher Jurvetson. Retrieved 20 November 2005.
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