What is PFC in PSU?

[ATIFanboy]

What is PFC in PSU? And is there much point to buy PSU with PFC?

 

[Davegod]

IIRC:

PFC = power factor correction, er or something. Basically it monitors the volateg rails and increases/lowers them if theyre too low/high. Or so i thought anyway.

google found http://www.endpcnoise.com/cgi-bin/e/pfc.html
or perhaps better http://www.dansdata.com/gz028.htm

 

[Zepper]

PFC is power factor correction. On a reactive load like a PSU, the voltage and current load curves don't line up. A pfc correction circuit tries to make the PSU look more like a passive load (basically a resistor) to your AC power, where the curves line up - the better PFC circuits are called active. If your electric company's power meter is of a certain type, you can save on power costs over a large number of PSUs as the power draw isn't spread as widely over time.
. PFC PSUs are required in Europe. For one or two PSUs in a home, the savings might be noticeable over a year's period, but not significant.
.bh.

 

[GalvanizedYankee]

Originally posted by: Zepper
PFC is power factor correction. On a reactive load like a PSU, the voltage and current load curves don't line up. A pfc correction circuit tries to make the PSU look more like a passive load (basically a resistor) to your AC power, where the curves line up - the better PFC circuits are called active. If your electric company's power meter is of a certain type, you can save on power costs over a large number of PSUs as the power draw isn't spread as widely over time.
. PFC PSUs are required in Europe. For one or two PSUs in a home, the savings might be noticeable over a year's period, but not significant.
.bh.

That is a very good answer. I spent over an hour reading up on PFC and that was the conclusion. So when I put together a comp for my gal, it makes no difference.

 

[Zepper]

Well, the Active PFC PSUs are generally a mfr's top line products, so the overall quality should be better. Given a choice and the price being not too much more, I would go for it. Sometimes the PFC PSUs have a better efficiency ratio as well - std PSUs are usually in the 65% range while active PFC models are often over 70% efficient. Meaning less waste heat.
.bh.

 

[ATIFanboy]

Originally posted by: Zepper
Sometimes the PFC PSUs have a better efficiency ratio as well - std PSUs are usually in the 65% range while active PFC models are often over 70% efficient.

I wounder how this efficientcy calculated.

 

[Davegod]

presumably a complicated measurement version of 1 - ([watts going in minus watts going out] / watts going in).

...or would it be amps? bleh who cares anyway