08-11-2005, 11:27 PM
Hi,
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
Roland,Aug 11 2005, 01:45 PM Wrote:Remember, if you're only using 400W, you're wasting the other 260W. And, on top of that, if the efficiency is only, say, 65%, you're blowing off a full 231W of power as waste heat! Keep this in mind when choosing a PSU.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.
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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
How big was the aquarium in Noah's ark?