Talk:Power Supply Unit (Computer)

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Contents 1 No mention of... 2 Ideas for improvement 3 PFC 4 MTBF 5 Laptop supplies 6 neutraility of the Dell refference 7 power measurement 8 Label 9 Removal of paragraph about modular cabling creating high resistance. 10 Few points 11 Incorrect Information 12 Rename article to Power Supply Unit (Computer)

[edit] No mention of...

• Most PSU I think have like 4x 12v-lines.
• Does not mention EPS12V.
• Does not mention Power_Good signal (sometimes called Power_OK or PWR_OK).
• 8-pin Molex connectors for modern CPUs? Story Weaver 00:28, 17 December 2006 (UTC)

Most PSU's don't have 4 independent 12v lines, in fact most high end power supplies have 3x 12v lines, if that. I'm not sure what you're getting at with an "8pin molex connector for CPUs". --71.113.162.164 01:27, 5 February 2007 (UTC)

[edit] Ideas for improvement

• General clean up.
• Get some wiring diagrams of the different connectors.
• Clarify distinction between different connectors, and list standards such as EPS+12v etc.

Any other ideas would be appreciated, as well as consideration of this list. Damien Shiest 20:26, 28 November 2006 (UTC)

The "Things to consider" section needs to be changed from a list to something else, right now it seems very un-encyclopedic. --71.113.162.164 01:27, 5 February 2007 (UTC)

I'd like to add to your list a discussion of pre-ATX power supply designs, such as AT power supplies. I can think of two differences right now: the motherboard power connector (was a pair of connectors, usually wired in parallel, unlike today's 20/24 pin block) and the hardwired power switch. — EagleOne\^Talk 03:42, 5 May 2007 (UTC)

Yes, the addition of that information would be good. I am not sure how to structure the article, have an article for AT and one for ATX, or have just computer power supply, and have chapters for AT and chapter for ATX, or just have it all together. Please feel free to improve the article. -- Frap 10:02, 5 May 2007 (UTC)

Aside of organizing the article, I added a section for the differences between AT and ATX power supplies. Feel free to expand or clarify. Thief12 03:15, 12 July 2007 (UTC)

[edit] PFC

Curious about the power factor corrections... if a power supply does not indicate whether it has PFC or not, is it just "passive PFC" or is it "no PFC?" Secondly, isn't PFC required on all power supplies sold in Europe? ---Ransom (--71.4.51.150 23:10, 6 December 2006 (UTC))

Yes, all PSU sold in Europe must have PFC. So I assume if it does not mention anything about PFC, it is passive PFC. Active PFC is better and less common. -- Frap 21:53, 11 December 2006 (UTC)

No, we cannot assume passive PFC for those unindicated PSUs. Some are just regular PSUs without any form of PFC. Kiwi8 12:56, 18 January 2007 (UTC)

Since 2001, the IEC standard 61000-3-2 came into effect in Europe any new electronic equipment consuming more than 75Watts has to meet certain standards for harmonic content. This basically mandated some form of PFC. All of Britain, Japan and China have adopted similar standards though I know of no standard for the US.

Given 2001 isn't that long ago some older PSUs without any PFC may still be sold (illegally now I imagine) in those territories that have these rules on harmonics. ps: as a geek I have opened PSUs and replaced the fans with LED fans for case mods. Stuff the warranty - see the light. Ttiotsw 13:47, 18 January 2007 (UTC)

Yes, but as u said, it is in certain countries. In Singapore here we still have regular PSUs without any PFC on sale. Thus the statement about unindicated PSUs implying passive PFC cannot apply across the board. Kiwi8 14:14, 18 January 2007 (UTC)

[edit] MTBF

Looking at the MTBF, I think 100K hours is a bit unrealistic. Antec PSUs, which are higher end, are rated at 80K MTBF. Anyone else have any thoughts? - MSTCrow 08:29, 7 December 2006 (UTC)

I agree, Antec generally has higher quality PSUs, and rates them very realistically, I think the section on MTBF should be removed, unless it is further explained. --71.113.162.164 01:27, 5 February 2007 (UTC)

I heard Antec have different manufacturer of the supplies for different lines/products. And that some are good, some are bad. -- Frap 11:31, 5 February 2007 (UTC)

I think 100kh MTBF is not in any way a meaningful number. This is about 20 years. And this is supposed to be the MEAN time between failure, with all the DOA units factored in? Have you ever seen the insides of a PSU after 5 years? The .. dust? Did I mention the dust? And sometimes the layers of smoke residue? I think whether they tell you 100k hours or 200k hours, or 258.2 k hours -- who is to check that number, when 80% of PSUs get junked after 3 years anyway when the industry figures out they need just another "standard" and new, new, all new. —The preceding unsigned comment was added by 145.253.2.234 (talk • contribs) 13:29, June 14, 2007 (UTC)

[edit] Laptop supplies

The article currently does not mention laptop power supplies, which are quite different. It is particularly important to cover them, because they are generally much more energy efficient than desktop computers. Also, there should be mention of specialized low-power supplies, such as used in carputers.-69.87.202.60 12:25, 17 May 2007 (UTC)

I just added a section for laptop power supplies. Feel free to expand or clarify. Thief12 03:15, 12 July 2007 (UTC)

[edit] neutraility of the Dell refference

at the end of the first paragraph, there are references to dell producing non-standard ATX pinouts, and sugguesting it was an attempt to punish consumers using non-dell parts. first, the reference is speculation, as there is no evidence that it wasn't a cost-saving design decision that made a stupid decision of reusing connectors. secondly, compaq did this with many componets right up until the HP buyout, but it's not mentioned here. dell is neither the do-no-wrong company, nor the evil empire. --66.69.175.41 13:20, 12 June 2007 (UTC)

Agreed, I think we should remove it. The practice isn't limited to DellAchilles2.0 05:00, 9 July 2007 (UTC)

[edit] power measurement

Is there any way of measuring the power being supplied by a system's PSU at a given time? Drutt 18:42, 27 June 2007 (UTC)

I'm not sure about that, but you can use a device to measure the power being used by a PSU. The Kill-a-Watt electricity usage monitor is such a device. Some PSUs have also been tested for their energy efficiency at different loads. If you have that information you could calculate how much power your PSU was supplying based on the number of watts being used and the % efficiency at the % capacity of the load.

Mspandana 06:00, 4 August 2007 (UTC)

The output is just DC. Use an ammeter on the various output lines (12v, 5v, etc.) There are also special devices for testing power supplies that allow one to provide reference loads and more conveniently measure the outputs also. See for instance the power supply reviews at silentpcreview.com Zodon (talk) 09:42, 18 February 2008 (UTC)

[edit] Label

Example ATX power supply label

AC Input	100–240 Vac — 10–5A 50–60Hz
DC Output	+3.3V	+5V	+12V1	+12V2	+12V3	+12V4	−12V	+5Vsb
Max Output Current	36A (118.8 W)	30A (150 W)	18A (216 W)	18A (216 W)	18A (216 W)	18A (216 W)	0.5A (6 W)	3.0A (15 W)
Max Combined Power	155W		680W				20W
Total Power	700W

[edit] Removal of paragraph about modular cabling creating high resistance.

I've removed the statements about modular cabling creating high resistance because these claims are biased. This claim is made by a company that themselves does not produce modular power supplies. I just found out, however, that there can be a sginificant amount of resistance across modular connectors, but it depends on the age of the PSU, the manufacturer, and the number of times the plug was insterted/removed. The article is found here: http://www.motherboards.org/articles/guides/1488_11.html I wasn't sure whether this was reliable, however, so I left my edit alone. I know anyone can make a website, but it looks like a long-running and well-established one, and I wanted to be sure. Thanks. Totakeke423 (talk) 05:35, 30 March 2008 (UTC)

I'm kind of wondering how an unused connector port can provide ANY resistance.----Asher196 (talk) 05:01, 30 March 2008 (UTC)

I think it's only for the ones that are connected. I think the resistance comes from loose connections.Totakeke423 (talk) 05:36, 30 March 2008 (UTC)

I rewrote the section I removed about modular cabling and added a source website. Totakeke423 (talk) 07:37, 30 March 2008 (UTC)

[edit] Few points

"Quality construction consisting of industrial grade electrical components and/or a higher speed fan can help to contribute to a higher MTBF rating by keeping critical components cool, thus preventing the unit from overheating. Overheating is a major cause of PSU failure."

OTOH higher speed fans dont last as long, and fan failure is also a cause of many PSU failures. The best PSUs use larger than usual lower speed fans.

"While it is hoped that eliminating the excess cables will improve the flow of cooling air inside the computer case,"

only to a trivial extent, not really a significant issue

"While it's relatively easy and inexpensive to lubricate/replace a fan, opening a power supply can be dangerous and usually voids the warranty, so it's best left to a professional."

a dubious conclusion, and clearly wrong for a lot of people. Tabby (talk) 12:59, 10 May 2008 (UTC)

[edit] Incorrect Information

"Using a power supply that is larger than necessary can significantly increase operating costs by wasting energy."

Is completley false, a power supply does not draw more electricity than it needs to. A 600W psu will not use anymore power than a 300W psu when powering the same hardware.

"Most power supplies have an efficienty at about 50% of the rated power load."

Makes no sense. What does it mean? Their efficiency is highest at 50% load? They become more efficient after 50% load? They become less efficient after 50% load?

Comrinec (talk) 01:04, 31 May 2008 (UTC)

Yes, it varies but it generally peaks at a certain percentage and below and above that, it may be have lower efficiency. -- Frap (talk) 02:19, 31 May 2008 (UTC)

[edit] Rename article to Power Supply Unit (Computer)

I think that this article has got the wrong name. The technical name for computer power supplys is power supply unit (PSU). I propose we rename the article as above. Do people agree? —Preceding unsigned comment added by WikiJonathanpeter (talk • contribs) 19:25, 31 May 2008 (UTC)

I agree. I don't like the current name of the article.Asher196 (talk) 23:15, 31 May 2008 (UTC)

Thank you. Since noone has left a negative comment regarding this, I will go ahead with the change. Thanks. WikiJonathanpeter (talk) 22:05, 12 June 2008 (UTC)