OT question for electronics wizards

From: Christian Fandt <cfandt_at_netsync.net>
Date: Mon Dec 21 21:00:35 1998

At 19:11 12/21/98 -0700, you wrote:
>Hi. Just a quick question which is kind of off topic - with switched power
>supplies like those in modern PCs, when it says the input current is 7 amps at
>115 volts, is that the constant no matter how much the computer itself draws,

That's the rating of the mains input when the power supply is fully loaded.
This means that when all the outputs are run at their maximum design rating
(using example values quickly thought up: 30 Amps on the +5V, 7 Amps on the
+12V, 0.5 A. on the -12V) about 7 Amps would be drawn from the mains.

Having the PC box absolutely stuffed full of the really old high current
draw boards and a couple of old technology hard drives could push the mains
draw towards the max mains input rating. I've never been able to overload a
200 Watt PC PSU (yet).

>or the maximum, no matter what? If it's the latter my computer room is
>going to need more circuits in a big hurry...

I imagine if your hardware is quite modern, a 7 Amp draw from each of your
PC boxes is not at all possible. I would guess half that nowadays, at most,
for a typical PC setup. Russ B.? You're one of the folks who work with a
lot of PC gear. Are my experiences and conclusions in line with what you've

Regards, Chris
-- --
Christian Fandt, Electronic/Electrical Historian
Jamestown, NY USA cfandt_at_netsync.net
Member of Antique Wireless Association
        URL: http://www.ggw.org/freenet/a/awa/
Received on Mon Dec 21 1998 - 21:00:35 GMT

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