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Old 04-25-2013, 11:19 AM   #70
momaka
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Join Date: May 2008
City & State: VA (NoVA)
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Default Re: What could cause this PSU to output 12.5V on the 12V?

Get a 40W to 100W incandescent light bulb and some wire. See attached diagram for wiring (all MS Paint style ).
NOTE: BE EXTREMELY CAREFUL AROUND THE BULB WHEN IT'S PLUGGED IN!


Quote:
Originally Posted by Pentium4
It wouldn't just pop the fuse?
No, because the light bulb is in series with the PSU. So if any component in the PSU tries to pull too much current due to a fault, the impedance of the PSU will become much lower relative to the bulb's impedance. This will make the light bulb glow. It pretty much works like a simple series resistor voltage divider.
Attached Images
File Type: png series incandescent bulb trick.PNG (6.0 KB, 698 views)

Last edited by momaka; 04-25-2013 at 11:30 AM..
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