Alternating current - Revision history

Jmdonev at 20:15, 10 July 2023

2023-07-10T20:15:52Z

← Older revision		Revision as of 20:15, 10 July 2023
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	[[Category:Done 2018-08-03]]		[[Category:Done 2018-08-03]]
	[[category:Phets]]		[[category:Phets]]
	<onlyinclude>'''Alternating current (AC)''' is the type of [[electric current]] generated by the vast majority of power plants and used by most power [[Distribution grid\|distribution system]]s. Alternating current is ~~cheaper~~ to generate and ~~has fewer~~ energy losses than [[direct current~~]] when transmitting [[electricity~~]] over [[grid\|~~long~~ distances]].</onlyinclude><ref>M. Brain et al. ''How Electricity Works'' [Online]. Available:http://science.howstuffworks.com/electricity8.htm</ref> Although for very [[HVDC transmission\|long distances]] (more than 1000 km), direct current can often be better. As opposed to direct current, the direction and [[amperage]] of alternating current changes many times a [[second]].		<onlyinclude>'''Alternating current (AC)''' is the type of [[electric current]] generated by the vast majority of power plants and used by most power [[Distribution grid\|distribution system]]s. Alternating current is easier to generate and transmitting alternating current leads to lower energy losses than [[direct current]] over [[grid\|distances]] more than a few metres.</onlyinclude><ref>M. Brain et al. ''How Electricity Works'' [Online]. Available:http://science.howstuffworks.com/electricity8.htm</ref> Although for very [[HVDC transmission\|long distances]] (more than 1000 km), direct current can often be better. As opposed to direct current, the direction and [[amperage]] of alternating current changes many times a [[second]].

	== Properties ==		== Properties ==

Jmdonev: 1 revision imported

2018-09-03T22:23:43Z

1 revision imported

← Older revision	Revision as of 22:23, 3 September 2018
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energy>Jmdonev at 21:15, 26 August 2018

2018-08-26T21:15:26Z

← Older revision		Revision as of 21:15, 26 August 2018
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			[[Category:Done 2018-08-03]]
	[[category:Phets]]		[[category:Phets]]
	<onlyinclude>'''Alternating current (AC)''' is the type of [[electric current]] generated by the vast majority of power plants and used by most power [[distribution system]]s. Alternating current is cheaper to generate and has fewer energy losses than [[direct current]] when transmitting [[electricity]] over [[grid\|long distances]].</onlyinclude><ref>M. Brain et al. ''How Electricity Works'' [Online]. Available:http://science.howstuffworks.com/electricity8.htm</ref> Although for very [[HVDC transmission\|long distances]] (more than 1000 km), direct current can often be better. As opposed to direct current, the direction and [[amperage]] of alternating current changes many times a [[second]].		<onlyinclude>'''Alternating current (AC)''' is the type of [[electric current]] generated by the vast majority of power plants and used by most power [[Distribution grid\|distribution system]]s. Alternating current is cheaper to generate and has fewer energy losses than [[direct current]] when transmitting [[electricity]] over [[grid\|long distances]].</onlyinclude><ref>M. Brain et al. ''How Electricity Works'' [Online]. Available:http://science.howstuffworks.com/electricity8.htm</ref> Although for very [[HVDC transmission\|long distances]] (more than 1000 km), direct current can often be better. As opposed to direct current, the direction and [[amperage]] of alternating current changes many times a [[second]].

	== Properties ==		== Properties ==
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	== References==		== References==
	<references/>		<references/>
	~~[[Category:Done 2018-04-30]]~~
	[[category:uploaded]]		[[category:uploaded]]

Jmdonev: 1 revision imported

2018-05-11T18:17:02Z

1 revision imported

← Older revision	Revision as of 18:17, 11 May 2018
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Jmdonev at 17:51, 9 May 2018

2018-05-09T17:51:55Z

← Older revision		Revision as of 17:51, 9 May 2018
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	[[category:Phets~~]][[Category:Done 2016-01-15~~]]		[[category:Phets]]
	<onlyinclude>'''Alternating current (AC)''' is the [[current]] generated by the vast majority of power plants and used by most power [[distribution system]]s~~, as it~~ is cheaper to generate and has fewer energy losses than [[direct current]] when transmitting [[electricity]] over long distances.</onlyinclude><ref>M. Brain et al. ''How Electricity Works'' [Online]. Available:http://science.howstuffworks.com/electricity8.htm</ref> Although for very long distances, direct current can often be better. As opposed to direct current, the direction and [[amperage]] of alternating current changes many times a [[second]].		<onlyinclude>'''Alternating current (AC)''' is the type of [[electric current]] generated by the vast majority of power plants and used by most power [[distribution system]]s. Alternating current is cheaper to generate and has fewer energy losses than [[direct current]] when transmitting [[electricity]] over [[grid\|long distances]].</onlyinclude><ref>M. Brain et al. ''How Electricity Works'' [Online]. Available:http://science.howstuffworks.com/electricity8.htm</ref> Although for very [[HVDC transmission\|long distances]] (more than 1000 km), direct current can often be better. As opposed to direct current, the direction and [[amperage]] of alternating current changes many times a [[second]].

			== Properties ==
	[[File:AC.gif\|framed\|right\|Figure 1. An animation from a PhET simulation<ref>http://phet.colorado.edu/sims/circuit-construction-kit/circuit-construction-kit-ac_en.jnlp</ref> of alternating current which has been slowed down considerably. See [[direct current]] for a comparison.]]		[[File:AC.gif\|framed\|right\|Figure 1. An animation from a PhET simulation<ref>http://phet.colorado.edu/sims/circuit-construction-kit/circuit-construction-kit-ac_en.jnlp</ref> of alternating current which has been slowed down considerably. See [[direct current]] for a comparison.]]
	~~== Properties ==~~
	An alternating current will flip the direction of [[charge]] flow (60 times a second in North America (60 [[Hz]]) and 50 times a second in Europe (50 Hz)). This is usually caused by a sinusoidally varying current and voltage that reverses directions, creating a periodic back and forth motion for the current (see Figure 1). Despite this current flowing back and forth many times a second, the energy still essentially flows continuously from the power plant to the electronic devices.		An alternating current will flip the direction of [[charge]] flow (60 times a second in North America (60 [[Hz]]) and 50 times a second in Europe (50 Hz)). This is usually caused by a sinusoidally varying current and voltage that reverses directions, creating a periodic back and forth motion for the current (see Figure 1). Despite this current flowing back and forth many times a second, the energy still essentially flows continuously from the power plant to the electronic devices.

	A major advantage of alternating current is that its [[voltage]] can be modified relatively easily using a [[transformer]], which allows power to be transmitted at very high voltages before being taken down to safer voltages for commercial and residential use.<ref>''What is alternating current (AC)?'' [Online]. Available:http://www.allaboutcircuits.com/vol_2/chpt_1/1.html</ref> This minimizes energy losses, as shown below<ref>''Power Dissipated in a Resistor'' [Online]. Available: http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elepow.html#c2</ref> (see [[residential household circuit]]s for more details):		A major advantage of alternating current is that its [[voltage]] can be modified relatively easily using a [[transformer]], which allows power to be transmitted at very high voltages before being taken down to safer voltages for commercial and residential use.<ref>''What is alternating current (AC)?'' [Online]. Available:http://www.allaboutcircuits.com/vol_2/chpt_1/1.html</ref> This minimizes energy losses, as shown below<ref>''Power Dissipated in a Resistor'' [Online]. Available: http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elepow.html#c2</ref> (see [[residential household circuit]]s for more details):

	<m> P_{lost} = I^{2}R </m>		::<math> P_{lost} = I^{2}R </math>

	<m> P=IV </m>		The power transmitted down the line however has a different expression:
			::<math> P_{transmitted}=IV </math>

	:::* ''P'' is the [[power]], measured in [[watt]]s		:::* ''P'' is the [[power]], either lost or transmitted and is measured in [[watt]]s
	:::* ''I'' is the [[current]] through the wire, measured in [[ampere]]s		:::* ''I'' is the [[electric current]] through the wire, measured in [[ampere]]s
	:::* ''V'' is the [[voltage]], measured in [[volt]]s		:::* ''V'' is the [[voltage]], measured in [[volt]]s
	:::* ''R'' is the [[resistance]], measured in [[ohm]]s		:::* ''R'' is the [[resistance]], measured in [[ohm]]s
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	<div style="position: relative; width: 300px; height: 226px;"><a href="http://phet.colorado.edu/sims/circuit-construction-kit/circuit-construction-kit-ac_en.jnlp" style="text-decoration: none;"><img src="http://phet.colorado.edu/sims/circuit-construction-kit/circuit-construction-kit-ac-screenshot.png" alt="Circuit Construction Kit (AC+DC)" style="border: none;" width="300" height="226"/><div style="position: absolute; width: 200px; height: 80px; left: 50px; top: 73px; background-color: #FFF; opacity: 0.6; filter: alpha(opacity = 60);"></div><table style="position: absolute; width: 200px; height: 80px; left: 50px; top: 73px;"><tr><td style="text-align: center; color: #000; font-size: 24px; font-family: Arial,sans-serif;">Click to Run</td></tr></table></a></div>		<div style="position: relative; width: 300px; height: 226px;"><a href="http://phet.colorado.edu/sims/circuit-construction-kit/circuit-construction-kit-ac_en.jnlp" style="text-decoration: none;"><img src="http://phet.colorado.edu/sims/circuit-construction-kit/circuit-construction-kit-ac-screenshot.png" alt="Circuit Construction Kit (AC+DC)" style="border: none;" width="300" height="226"/><div style="position: absolute; width: 200px; height: 80px; left: 50px; top: 73px; background-color: #FFF; opacity: 0.6; filter: alpha(opacity = 60);"></div><table style="position: absolute; width: 200px; height: 80px; left: 50px; top: 73px;"><tr><td style="text-align: center; color: #000; font-size: 24px; font-family: Arial,sans-serif;">Click to Run</td></tr></table></a></div>
	</html>		</html>

			== For further reading ==
			For further information please see the related pages below:
			*[[Direct current]]
			*[[Energy for electricity by country]]
			*[[Electrical grid]]
			*[[Electric generator]]
			*[[Special:Random\|or explore a random page!]]


	== References==		== References==
	<references/>		<references/>
	[[Category:~~Uploaded~~]]		[[Category:Done 2018-04-30]]
			[[category:uploaded]]

Jmdonev: 1 revision imported

2016-02-18T04:31:03Z

1 revision imported

← Older revision	Revision as of 04:31, 18 February 2016
(No difference)

Jmdonev at 20:27, 22 December 2015

2015-12-22T20:27:50Z

← Older revision		Revision as of 20:27, 22 December 2015
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	[[category:Phets]]		[[category:Phets]][[Category:Done 2016-01-15]]
	[[Category:Done ~~2015~~-02-15]]
	<onlyinclude>'''Alternating current (AC)''' is the [[current]] generated by the vast majority of power plants and used by most power [[distribution system]]s, as it is cheaper to generate and has fewer energy losses than [[direct current]] when transmitting [[electricity]] over long distances.</onlyinclude><ref>M. Brain et al. ''How Electricity Works'' [Online]. Available:http://science.howstuffworks.com/electricity8.htm</ref> Although for very long distances, direct current can often be better. As opposed to direct current, the direction and [[amperage]] of alternating current changes many times a [[second]].		<onlyinclude>'''Alternating current (AC)''' is the [[current]] generated by the vast majority of power plants and used by most power [[distribution system]]s, as it is cheaper to generate and has fewer energy losses than [[direct current]] when transmitting [[electricity]] over long distances.</onlyinclude><ref>M. Brain et al. ''How Electricity Works'' [Online]. Available:http://science.howstuffworks.com/electricity8.htm</ref> Although for very long distances, direct current can often be better. As opposed to direct current, the direction and [[amperage]] of alternating current changes many times a [[second]].

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	As seen in the first equation, the power lost through [[electrical transmission\|transmission]] is proportional to the square of the current through the wire. Therefore, it is preferable to minimize the current through the wire so that the energy loss is reduced. Of course, minimizing the [[resistance]] would reduce the energy lost as well, but the current has a much larger impact on the amount of energy lost due to its value being squared. The second equation shows that if voltage is increased, the current is decreased equivalently to transmit the same power. Hence, the voltage through transmission lines is very high, which reduces the current, which in turn minimizes the [[energy]] lost through transmission. This is why alternating current is preferred over direct current for transmitting [[electricity]], as it is much cheaper to change the voltage of an alternating current. However, there is a limit at which it is no longer advantageous to use alternating current over direct current (see [[HVDC transmission]]).		As seen in the first equation, the power lost through [[electrical transmission\|transmission]] is proportional to the square of the current through the wire. Therefore, it is preferable to minimize the current through the wire so that the energy loss is reduced. Of course, minimizing the [[resistance]] would reduce the energy lost as well, but the current has a much larger impact on the amount of energy lost due to its value being squared. The second equation shows that if voltage is increased, the current is decreased equivalently to transmit the same power. Hence, the voltage through transmission lines is very high, which reduces the current, which in turn minimizes the [[energy]] lost through transmission. This is why alternating current is preferred over direct current for transmitting [[electricity]], as it is much cheaper to change the voltage of an alternating current. However, there is a limit at which it is no longer advantageous to use alternating current over direct current (see [[HVDC transmission]]).

	== Uses==		==Uses and Advantages==
	Most devices (large factory dynamos for example) that are directly connected to a [[grid]] operate on alternating current, and [[electrical outlet]]s in homes and commercial areas supply alternating current as well. Devices that require direct current, like laptops, usually have an [[AC adapter]] that converts alternating current to [[direct current]].<ref>''What's the difference between AC and DC?'' [Online]. Available: http://engineering.mit.edu/ask/what%E2%80%99s-difference-between-ac-and-dc</ref>		Most devices (large factory dynamos for example) that are directly connected to the [[electrical grid]] operate on alternating current, and [[electrical outlet]]s in homes and commercial areas supply alternating current as well. Devices that require direct current, like laptops, usually have an [[AC adapter]] that converts alternating current to [[direct current]].<ref>''What's the difference between AC and DC?'' [Online]. Available: http://engineering.mit.edu/ask/what%E2%80%99s-difference-between-ac-and-dc</ref>

			Alternating current is the current of choice globally as it has many clear advantages compared to direct current. For a full breakdown of differences between the two, see [[AC vs DC]]. Some advantages include:<ref>Private communication with M. Pigman power engineer for Tacoma Power, Sept. 17th, 2015.</ref>

			*Cheap and efficient voltage stepping by use of [[transformer]]s. As explained above this allows for [[energy efficiency\|energy efficient]] [[electrical transmission]] via powerlines. This efficient transmission saves power companies and the consumer lots of money, and helps reduce [[pollution]] since [[power plant]]s do not need to make up for lost electricity by using more [[fuel]].
			*Low maintenance costs of high speed AC motors.
			*Easy to interrupt the current (ie. with a [[circuit breaker]]) due to the current going to zero naturally every 1/2 cycle. For example, a circuit breaker can interrupt about 1/20th as much DC as AC current.

	==Phet Simulation==		==Phet Simulation==

J.williams: 1 revision imported

2015-08-26T21:30:45Z

1 revision imported

← Older revision	Revision as of 21:30, 26 August 2015
(No difference)

J.williams at 16:40, 12 August 2015

2015-08-12T16:40:21Z

New page

[[category:Phets]]
[[Category:Done 2015-02-15]]
<onlyinclude>'''Alternating current (AC)''' is the [[current]] generated by the vast majority of power plants and used by most power [[distribution system]]s, as it is cheaper to generate and has fewer energy losses than [[direct current]] when transmitting [[electricity]] over long distances.</onlyinclude><ref>M. Brain et al. ''How Electricity Works'' [Online]. Available:http://science.howstuffworks.com/electricity8.htm</ref> Although for very long distances, direct current can often be better. As opposed to direct current, the direction and [[amperage]] of alternating current changes many times a [[second]].

[[File:AC.gif|framed|right|Figure 1. An animation from a PhET simulation<ref>http://phet.colorado.edu/sims/circuit-construction-kit/circuit-construction-kit-ac_en.jnlp</ref> of alternating current which has been slowed down considerably. See [[direct current]] for a comparison.]]
== Properties ==
An alternating current will flip the direction of [[charge]] flow (60 times a second in North America (60 [[Hz]]) and 50 times a second in Europe (50 Hz)). This is usually caused by a sinusoidally varying current and voltage that reverses directions, creating a periodic back and forth motion for the current (see Figure 1). Despite this current flowing back and forth many times a second, the energy still essentially flows continuously from the power plant to the electronic devices.

A major advantage of alternating current is that its [[voltage]] can be modified relatively easily using a [[transformer]], which allows power to be transmitted at very high voltages before being taken down to safer voltages for commercial and residential use.<ref>''What is alternating current (AC)?'' [Online]. Available:http://www.allaboutcircuits.com/vol_2/chpt_1/1.html</ref> This minimizes energy losses, as shown below<ref>''Power Dissipated in a Resistor'' [Online]. Available: http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elepow.html#c2</ref> (see [[residential household circuit]]s for more details):

<m> P_{lost} = I^{2}R </m>

<m> P=IV </m>

:::* ''P'' is the [[power]], measured in [[watt]]s
:::* ''I'' is the [[current]] through the wire, measured in [[ampere]]s
:::* ''V'' is the [[voltage]], measured in [[volt]]s
:::* ''R'' is the [[resistance]], measured in [[ohm]]s

As seen in the first equation, the power lost through [[electrical transmission|transmission]] is proportional to the square of the current through the wire. Therefore, it is preferable to minimize the current through the wire so that the energy loss is reduced. Of course, minimizing the [[resistance]] would reduce the energy lost as well, but the current has a much larger impact on the amount of energy lost due to its value being squared. The second equation shows that if voltage is increased, the current is decreased equivalently to transmit the same power. Hence, the voltage through transmission lines is very high, which reduces the current, which in turn minimizes the [[energy]] lost through transmission. This is why alternating current is preferred over direct current for transmitting [[electricity]], as it is much cheaper to change the voltage of an alternating current. However, there is a limit at which it is no longer advantageous to use alternating current over direct current (see [[HVDC transmission]]).

== Uses==
Most devices (large factory dynamos for example) that are directly connected to a [[grid]] operate on alternating current, and [[electrical outlet]]s in homes and commercial areas supply alternating current as well. Devices that require direct current, like laptops, usually have an [[AC adapter]] that converts alternating current to [[direct current]].<ref>''What's the difference between AC and DC?'' [Online]. Available: http://engineering.mit.edu/ask/what%E2%80%99s-difference-between-ac-and-dc</ref>

==Phet Simulation==
The [http://phet.colorado.edu/ University of Colorado] has graciously allowed us to use the following Phet simulation that explores how alternating current works.
<html>
<div style="position: relative; width: 300px; height: 226px;"><a href="http://phet.colorado.edu/sims/circuit-construction-kit/circuit-construction-kit-ac_en.jnlp" style="text-decoration: none;"><img src="http://phet.colorado.edu/sims/circuit-construction-kit/circuit-construction-kit-ac-screenshot.png" alt="Circuit Construction Kit (AC+DC)" style="border: none;" width="300" height="226"/><div style="position: absolute; width: 200px; height: 80px; left: 50px; top: 73px; background-color: #FFF; opacity: 0.6; filter: alpha(opacity = 60);"></div><table style="position: absolute; width: 200px; height: 80px; left: 50px; top: 73px;"><tr><td style="text-align: center; color: #000; font-size: 24px; font-family: Arial,sans-serif;">Click to Run</td></tr></table></a></div>
</html>

== References==
<references/>
[[Category:Uploaded]]