08-12-2005, 03:01 AM
Pete,Aug 11 2005, 06:27 PM Wrote:Hi,
Sorry, but it doesn't work that way -- believe me, I've tested. As long as you are drawing enough current to regulate the output, the input power will be equal to the output power *that you are actually using* divided by the efficiency. So, using your example, if I'm using 400W at 65% efficiency, I'll be sucking 615W from the wall.
Right. Rushed post. Sorry. I don't know what I was thinking - actually, I don't think I was. :P It's been too long of a week.
Quote:Actual efficiencies for switching power supplies are much higher than that. More like 80-90% (link and link). And the efficiency usually is best if you're using the PS at 1/3 to 2/3 of its rating. Below 1/3 and you're using proportionately too much power to regulate. Above 2/3 the PS starts running hot and that kills your efficiency (unless you want a space heater :) ).
--Pete
I don't think THG would quite agree with you, but I'm too tired and busy to bother looking it up. Maybe their measuring system is different?
Side note: 11 PM and I have to be packed and on the road in ~9 - 11 hours, tops, for my vacation. God I hate the night before. :P
Roland *The Gunslinger*