On Mon, 28 Jun 1999 16:20:09 +0100, John Perkinton wrote:

>I need a space saving power supply for powering a pic chip and very little
>other components from the mains directly which will work in any country.
>I've been looking at the Harris Semiconductor HV-2405E which RS Components
>can supply, but due to the size on inline power resistor (5W) the heat
>disapation is very high, no use for plastic enclosures. Has anyone any other
>ideas, or should I just use a 240V-12V transormer, a bridge rectifier, a 35V
>470uF cap, and a 7805. This seems to work well on both 240V and 110V, but is
>rather large, or does anyone know of a supplier of ultra small transformers.
>

That 7805 is gonna cook just like that 5W resistor when the transformer
is being fed 240V!

Most computer power supplies will run on 120 or 240.  Perhaps a
small computer power supply might help.  There are surplus switcher
supplies around too that may help but in a smaller or larger version
depending on your needs. I think Jameco has plenty. http://www.jameco.com

My $.02US

Dan