# What is the difference between an ATX and ATX12v Power Supply?



## AhrenBa (Jul 21, 2005)

Hello,
I am looking to buy a new PSU. What is the difference between an ATX and ATX12v? And, how do I know which one I need? Thanks


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## AhrenBa (Jul 21, 2005)

Anyone?


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## pugmug (Jun 13, 2005)

This link should help explain the diff. http://compreviews.about.com/od/cases/a/ATX12VvATX.htm


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## AhrenBa (Jul 21, 2005)

pugmug said:


> This link should help explain the diff. http://compreviews.about.com/od/cases/a/ATX12VvATX.htm


Awesome! Thank you. That helps explain it a lot better!

In another post I had, I confirmed that a Dell 4700 could use an industry standard power supply. However, I noticed that the current power supply (from Dell) does not use the 20th pin on the mainboard connector which is the -5v pin, where as most PSU do. Someone was telling me that the -5v pin did not matter, but will it still effect the Dell, since it doesn't use it?

What should I do about this? What does the "-" sign mean anyways (before the voltage rating)? Will it hurt if the new PSU does have this pin? Thanks


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## Triple6 (Dec 26, 2002)

- is for negative.


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## AhrenBa (Jul 21, 2005)

Triple6 said:


> - is for negative.


Yes, but I mean what is the difference between the + and the -. Does the + bring power to the motherboard and the - take it away to somewhere else?

Since Dell does not have a pin #20 (-5v), will it effect anything? Is there a way to get around it if it does? Thanks


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## pugmug (Jun 13, 2005)

Oh, I remember you now. http://forums.techguy.org/hardware/443291-solved-trying-figure-out-if.html Ok,if you really want to know about the -5 volt rail then study these links as there will be a pop quiz later. lol. http://web2.murraystate.edu/andy.batts/ps/POWERSUPPLY.HTM , http://www.analog.com/library/analogDialogue/archives/29-3/consider.html and this PDF file here, http://www.nutsvolts.com/PDF_Files/PSRepair.pdf and good luck on your quiz. ps. no sleeping during study time allowed !


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## AhrenBa (Jul 21, 2005)

pugmug said:


> Oh, I remember you now. http://forums.techguy.org/hardware/443291-solved-trying-figure-out-if.html Ok,if you really want to know about the -5 volt rail then study these links as there will be a pop quiz later. lol. http://web2.murraystate.edu/andy.batts/ps/POWERSUPPLY.HTM , http://www.analog.com/library/analogDialogue/archives/29-3/consider.html and this PDF file here, http://www.nutsvolts.com/PDF_Files/PSRepair.pdf and good luck on your quiz. ps. no sleeping during study time allowed !


Lol, I knew I would get burned for asking this. But wouldn't you guys get more mad if I re-opened the other thread? Plus this is a different question . Thanks for the help though.


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