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Author Topic: watts  (Read 648 times)

regiment

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watts
« on: December 29, 2013, 02:04:01 PM »

  my sons friend transformer has gone bust all it has on the box is  12 volts five  watts what is that in amps   thanks
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malcolmfrary

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Re: watts
« Reply #1 on: December 29, 2013, 02:19:08 PM »

Watts is Volts times Amps
Doing arithmetic, it follows that Amps is Watts divided by Volts.
In this case, 5/12, or 0.42A, or 420mA.
More important, is it a transformer or a power unit or a power unit badly named as a transformer?  A transformer on its own gives out AC, a power unit gives out DC.  There might be a clue on the the thing it plugs into - if it has a "+" and a "-" by the socket, it wants DC.  420mA is usually just that bit too much for one of those cheap battery eliminators.  One of these http://www.ebay.co.uk/bhp/12v-500ma-power-supply might do the job, but might equally need the plug sorting.
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regiment

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Re: watts
« Reply #2 on: December 29, 2013, 05:29:22 PM »

thanks very much for answer
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NFMike

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Re: watts
« Reply #3 on: December 30, 2013, 12:43:02 AM »

Strictly speaking if it was (is) a transformer it should give the rating as 12V, 5VA. As it is given in Watts it is quite probably a DC power supply of some sort.
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