Re: Transformers

On Sat, 13 Aug 2005 17:52:05 -0700, Kitchen Man
<nannerbac@xxxxxxxxx> wrote:

>On Fri, 12 Aug 2005 21:19:45 -0700, "Rodney" <rdavies@xxxxxxxxxxxx>
>wrote:
>
>>I've noticed that a transformer with, say, a voltage rating of 10 volts can
>>sit at a considerable higher voltage than 10 volts if it is not under load.
>>Once a current is being drawn from it the voltage will drop to that
>>specified. I was thinking that a high wattage transformer, even though it
>>may be specified at 10 volts could sit at a much higher voltage if, even
>>under load, too small a current were being drawn from it. That is, if the
>>load were too small. The higher voltage could possible damage the load
>>circuit in some cases, I think. Please correct me if I'm wrong.
>
>Others have noted that you are using incorrect terminology - you are
>referencing an unregulated plug-in DC power supply. A lot of people
>call this a wall-wart, 'cause it tends to look like your wall is
>growing a wart when you plug one in. I think it's a silly name, but
>to call it a transformer is simply wrong.
>
>Now, on to your question. I have also noticed the same phenomenon,
>and I have wondered the same thing about what would happen if the
>rating of the supply was grossly in excess of the load attached. The
>following article is a very good reference for the question:
>
>http://www.glitchbuster.com/wallwart.htm

---
Here are some excellent data sheets with load curves. Takes the
mystery out of it.

http://www.tamuracorp.com/clientuploads/pdfs/pgs94-95.pdf
--
John Fields
Professional Circuit Designer
.

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