[Lab] AC adapter question

[Michael Ayukawa]

The spec sheet says 83% efficient.  It is a 25W supply so at most you will be dumping 5W.
The beauty of a switching supply is that you don't just dump the excess power like a linear supply.
But the quiescent losses will be there.

Regardless your challenge is to get rid of this heat.  Even at a few watts. 
A fan is a pretty good idea and 5V fans are plentiful.  
The supply does not suited to mount a passive heat sink.

It is a nice looking supply. It would be shame to have it melt down.  Or catch fire.
70C will feel very hot to touch (max rating).  

On 2013-07-11, at 6:49 PM, Britta Evans-Fenton <technical at artengine.ca> wrote:

> A little question about AC adapters.  
> 
> I have an artwork that I did that I used an AC adapter to get power.  It was on for 4 days during a show, and I was surprised on how hot it got.  (I almost burned myself).  I did have duct tape on it holding it to the back of a wall, so that may have been half the problem.
> 
> I'm showing the work again, but I'm wanting to make sure everything is safe.  I need to hide the adapter due to aesthetic reasons, so I wanted to create a little white box around it with air holes, and I was suggested a fan, although it if it getting hot due to over working, adding another fan might not be a good idea. 
> 
> It is only a bunch of IR leds that it is powering, so I'm surprised at the power I am needing.  
> 
> any help would be very well appreciated. 
>>> 
>>> Here is the Adapter I used : 
>>> http://www.digikey.ca/product-detail/en/VGS-25-5/102-1928-ND/2045659
>>> 
>>> Here are the IR LEDS:
>>> http://www.digikey.ca/product-detail/en/QED233/QED233-ND/187410
>>> 
>>> And the Resistors I have on them were 91 OHM 1/4W 5% CARBON FILM.
> 
> Britta
> Technical Coordinator 
> Artengine.ca
> 
> Ottawa Mini Maker Faire
> Aug. 31 & Sept. 1 2013
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