- Joined
- Feb 13, 2001
- Location
- Twin Cities
I'll give you the "Kmart" answer instead of the "Neiman Marcus" answer. ;D
This is "Trickle Down" regulation. The PSUs hardest challenge is to regulate the +5V output. It accomplishes this by varying the chopper drive to the transformer primary based upon the load on the +5V output. The +12V output shares this drive also. When demand on the +5V goes up, the drive goes up to accomodate it. Consequently, the +12V drive goes up also. That's why you hear the fans, running on the +12V speed up slightly when you load the CPU.
You need to place a nominal load on the +5V to get the drive pumped up to accomodate a large load on the +12V. Personally, if I was using a PC PSU to power a Pelt, and I might mention that I would not, I would put more like a 10A load on the +5V, not just a 1A load.
If you want the "Neiman Marcus" explanation, email me. It will take a page or two to explain Pulse Width Modulation Regulation.
Hoot
This is "Trickle Down" regulation. The PSUs hardest challenge is to regulate the +5V output. It accomplishes this by varying the chopper drive to the transformer primary based upon the load on the +5V output. The +12V output shares this drive also. When demand on the +5V goes up, the drive goes up to accomodate it. Consequently, the +12V drive goes up also. That's why you hear the fans, running on the +12V speed up slightly when you load the CPU.
You need to place a nominal load on the +5V to get the drive pumped up to accomodate a large load on the +12V. Personally, if I was using a PC PSU to power a Pelt, and I might mention that I would not, I would put more like a 10A load on the +5V, not just a 1A load.
If you want the "Neiman Marcus" explanation, email me. It will take a page or two to explain Pulse Width Modulation Regulation.
Hoot
The only reason I havn't broken down and gotten a good power suply like an Astron is because he pelt really isn't that big. It's only an 80w 12v 6a pelt. Thats well within the limits of a regular PSU. I'll take your advice and put a larger than 1 amp load on the 5v line. I will also go back to radio shack and explain to that kid why you need a load on the 5v line. I knew some of the reason why but not enough to convince him. He was a hard head anyways. "Oh I build servers as my second job" WHoopie do. Thanks Hoot.
