Model Boat Mayhem

Mess Deck: General Section => Chit-Chat => Topic started by: regiment on December 29, 2013, 02:04:01 pm

Title: watts
Post by: regiment 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

Title: Re: watts
Post by: malcolmfrary 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 (http://www.ebay.co.uk/bhp/12v-500ma-power-supply) might do the job, but might equally need the plug sorting.

Title: Re: watts
Post by: regiment on December 29, 2013, 05:29:22 pm

thanks very much for answer

Title: Re: watts
Post by: NFMike 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.