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Possible Duplicate:
Choosing power supply, how to get the voltage and current ratings?

Can I replace the power adapter of 12V/0.8A with one of 12V/2A?

I have a Digital device that uses a power adapter to 12V/0.8A, and it stopped working. Can I replace it with other adapter that is 2A? Would this work? And what effect would it have?

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user17731
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3 Answers3

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Yes. The device will only draw as much current as it requires. Just make sure that the polarity on the connector matches.

Ignacio Vazquez-Abrams
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Yes, with caution. 2A is quite a bit more (as opposed to a -LOT- more, like, say, 20A would be) than 0.8A. You device might not even have bothered with a proper fuse, thinking 'oh well, the power supply will limit to 0.8 A'.

Bobbi Bennett
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This question will probably have been closed next time you blink. It is asked often and not deemed a proper question by those who prognosticate on such things. As Ignacio says, no problem.

If the voltage is correct the target determines how much current to draw. In a very very few cases the equipment may rely on the power supply sagging under load to work correctly BUT such equipment is rare and should be shunned.

One case where it may matter is cheap power supplies for cheap appliances using NiCd or NimH batteries. Drills of say 12V to 24V rating may be like this. Such systems rely on the transformer open circuit voltage not exceeding the battery fully charged voltage "by much". They usually use unregulated supplies. Such systems cook their batteries if left connected when charged at the best of times. They will do so more happily if a higher current capacity supply is used. This is a very nasty method of battery charging and best avoided if possible.

Russell McMahon
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  • We made one question so that we do not answer this question constantly. The point of SE is not having to answer the same question over and over. It is why it beats mailing lists and forums in many types of questions, but in certain kinds like shopping that are person specific, it just does not fit well. – Kortuk Jan 09 '13 at 17:29