-5v and -12v not needed?

[Tengis]

They are fluctuating on my PSU, does that matter? I looked in the faq and it said they arent even included on some newer psus... so Im assuming I dont need them.


Sorry mods for all my posts in this section... Im just really tired and Im trying to figure some stuff out about PSUs.

 

[Vertigo Acid]

Yep, they fluctuate so much because there is no load on them. When switched-mode power supplies have no load on them, they can't regulate properly, hence what you are seeing. No worries mate

 

[gee]

Some soundcards and RS232 ports use them.

An old motherboard I had used negative voltage to power something in the CPU core regulator, and when I tried making a car PC out of it without the -5/-12 lines, the fucking thing popped a P166MMX on me

 

[Elledan]

Some soundcards and RS232 ports use them.

To be precise, EIA232 (serial) ports use +12V (HIGH) and -12V (LOW) for signaling.

-5V isn't really used by anything anymore, so it's missing on a number of PSUs (MicroATX, Mini-ITX and SFF PSUs, for example).

It kind of sucks when you want to use an ATX PSU for an AT system, though =/