View source for Ampere hour

[[Category:Done 2018-04-30]]
<onlyinclude>An '''ampere hour''' (abbreviated A<math>\cdot</math>h or amp hr) is a [[units|unit]] of electric [[charge]], usually used for [[battery|batteries]]. This unit combines the amount of [[current]] with how long that current can be sustained until the battery completely discharges.</onlyinclude><ref name=B>R.T.  Paynter, “Basic Electric Components and Meters,” in ''Introduction to Electricity'', 1rst ed. NJ: Prentice-Hall, 2011, ch. 3, sec. 3.4, pp. 90.</ref> Large batteries have several ampere hours but cell phones and other small devices have batteries with a total charge measured in milliampere hours. This measured quantity is called [[battery capacity]].<ref name=B/>

The number of amp-hours in a battery is found by multiplying the amount of current (in [[ampere]]s) by the time (in [[hour]]s) a given current could flow before the battery runs out. This calculation gives the total amount of charge transferred. This unit is useful since a battery will be able to supply current for a longer period of time, than say a [[capacitor]]. [[Chemical reaction]]s inside the battery are limited by the amount of material that can be eaten away, and how quickly, this means that to test the ampere hours of a battery one should use a low current relative to the battery's peak current capability. 

1 Ah = 3,600 [[Coulomb]]s

Often the amp hour is written on the side of a [[battery]], which has a [[voltage]] (often 1.5 [[volt|V]]). An ampere hour at 1 volt is a unit of [[energy]], specifically the [[watt-hour]] (1/1000th of a [[kWh]]).

To learn more about the ampere hour please see Dr. Rowlett's [http://www.unc.edu/~rowlett/units/dictA.html#ampere dictionary of units].

== For Further Reading ==
For further information please see the related pages below:
*[[Battery]]
*[[Electric charge]]
*[[Fuel cell]]
*[[Capacitor]]
*[[Electric current]]
* Or explore a [[Special:Random| random page!]]

==References==
{{Reflist}}
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