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Same ground, different voltages?
kahlid74:
--- Quote from: Nephasth on January 16, 2014, 12:00:53 am ---Ground is ground is ground.
--- End quote ---
I'm not electrically super savvy but while this is true, the question becomes whether the components can handle a different voltage coming back through right? If the IPAC is rated for 5V and you send 12 back through could there be components not expected this or are components on an electrical path only ever before the voltage and not on the ground path?
DeLuSioNal29:
Think of a how a molex connector is on a power supply. Both 12v and 5v share common ground, but have different voltages.
D
Sarver Systems:
--- Quote from: DeLuSioNal29 on January 16, 2014, 12:05:28 pm ---Think of a how a molex connector is on a power supply. Both 12v and 5v share common ground, but have different voltages.
D
--- End quote ---
And 2 different ground wires.
But, back inside the power supply itself, they are connected together.
So, to answer your question....ground is ground is ground. Just as was stated before.
Nephasth:
--- Quote from: kahlid74 on January 16, 2014, 11:47:56 am ---
--- Quote from: Nephasth on January 16, 2014, 12:00:53 am ---Ground is ground is ground.
--- End quote ---
I'm not electrically super savvy but while this is true, the question becomes whether the components can handle a different voltage coming back through right? If the IPAC is rated for 5V and you send 12 back through could there be components not expected this or are components on an electrical path only ever before the voltage and not on the ground path?
--- End quote ---
There is no voltage on ground. Ground is ground. Ground is not hot.
lilshawn:
all the black wires on a computer power supply are tied together. it's fine to attach them together.
in some cases where you have an external power supply brick, and you are having noise issues, you have to tie the negative voltage wire (-) to the ground of the computer power supply. make sure your output of your supply is isolated from line voltage before doing this.
you can even NOT use the black ground on the computer power supply. all the voltages are referenced together...for instance say you have some fans that make a ton of noise when running them at 12 volts, but won't start properly if you run them at 5 volts...you can attach the positive lead of the fan to the yellow 12 volt supply, and attach the negative lead to the red 5 volt line. your fan will run at 7 volts. (the difference of voltage between 5 volts and 12 volts.)
This is called ELECTRICAL POTENTIAL DIFFERENCE.
you can use this to your advantage by tapping all sorts of voltages in the power supply.
Positive on: + negative on = ___volts DC.
12 volts + 3.3v = 8.7v
5 volts + 3.3v = 1.7v
12 volts + -12 volts = 24 v
3.3 volts + -5 volts = 8.3 v
12 volts + -5 volts = 17 v.
PLEASE NOTE, if you decide to use the negative voltages of your supply, the maximum load is that of the NEGATIVE rail. so even though your +12 puts out 45 amps, the - 5 rail only puts out 900mA.... this means the maximum load on your "17 volt supply" should be UNDER 900mA.
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