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Battery current


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Batteries have different chemistries. Some are cheap and perform poorly (carbon-zinc) but others are expensive and perform better (alkaline). Which one?

Battery cells have many different sizes. The tiny ones can't supply much current.

Go to www.energizer.com and click on Technical Info at the top of the page. Then select the datasheet type from the list on the left side.

Their 9V alkaline battery has 6 tiny and skinny AAAA cells inside. It might give 500mA for one minute but the datasheet shows nearly 300mA for 1 hour and the voltage slowly drops to 6V. Or 10mA for 60 hours.

AA alkaline cells are much bigger than the tiny cells in a 9V battery and can supply about 6 times as much current or for about 6 times longer.

D alkaline cells are bigger again and give an extremely high current or last for a very long time.

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Hi Prateek,
Little batteries or wall-wart AC-DC adapters cannot give "any" amount of current because they have an internal resistance that limits the max current. The more current that is drawn then the lower becomes the voltage. A new little 9V alkaline battery can give about 500mA to a short for a few seconds. So its internal resistance when new is 9V/500mA= 18 ohms which keeps increasing (and the max current keeps decreasing) as the battery runs down.

A voltage source should have a current rating where its output voltage drops no more than a certain percentage with its rated current, and a rated max amount of current where damage to it won't occur.

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