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Psu Pfc


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So, someone asked me today what PFC does, and I had to think about it for a bit. I came up with:

 

P=I*V

P=I*V*cosO

So, when the phase is out (I against V) cosO is more, when it gets to 90* P=0

The PFC 'thingy' in the PSU corrects the phase so that it doesn't disturb the power system, in other works brings cosO back to 1.

 

Does that make any sense at all?

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PSU FAQ (scroll down to the last post)

571086[/snapback]

 

 

gotta ask ya, I know alot of PSU's but im sure you know more, so u live up to ur avater.

 

What are the most important things when looking for a power supply. brand name aside?

 

Amps on 12V rail

weight

efficiency

other features?

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More amps the better, the more rails the better.

Heavier the better (usually) as it indicates 'higher quality' components.

Dunno what you mean by efficiency -- cooling?

571171[/snapback]

 

 

So basically its what i thought. The efficiecy, I usally see a box for it at least on PSU @ newegg, it says efficiency then like 60-80% i usally see, but what is bad and good ranges?

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Here are more psu factors:

 

noise level

voltage accuracy

modular or not

braided vs sleeved vs regular cables

max number of power outputs

571301[/snapback]

 

Yes but that still doesn't help, what are good and bad ranges?

 

And the only good Modular PSU's ive seen are not to cheap.

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In terms of voltage accuracy, you want your rails to stay as close to their rating as possible. For example, you want your 12v rail to stay as close to 12v as possible; however, psu's aren't that accurate and the best like the antec neopower or pc power & cooling turbo deluxe have 12v rails @ 12.08v or 11.92v. 12.6v is the limit of the atx 2.0 spec and you'd never want a psu with voltages that inaccurate.

 

So basically, you want your rails to be no more than .2v away from their ratings no matter what. (ex. 12.20v on the 12v rail) Some psu's like the OCZ powerstream have adjustable voltage pots so you can tweak your voltages.

 

I hope this helps you. :)

Edited by Celcius

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