View Full Version : ATX power supply - load resistor - do I need one ?

18-08-2010, 11:32 AM

I'm using 2 Dell power supplies to provide 24 volts and found lots of info on the net on how to do this. The only thing some say you need a load resistor and other say just bridge black and green. I've seen some sites suggesting a 12 V car bulb across the +5Volt supply is enough. The Dell power supplies I'm using are from GX270 and are 20 pin on the motherboard connector.

Would the driver board put enough load or do I just not need a load resistor.



18-08-2010, 11:51 AM
The issue is that some ATX supplies power down the +12v rail if there is no load on the +5. The simplest way is to try it and see... if the 12v is rock solid without a load then fine, if not, try a car bulb on the +5 rail as suggested.

18-08-2010, 12:36 PM
When I've converted ATX PSU's in the past (hard wired jobbys) I've stuck a 10 ohm, 5-10W resistors (those heatsinked ones with screw down tabs) on the 5V rail, and screwed it inside the case.


Also hard wire the green wire to the GND (black)

If you want a quick way to test, just stick an old HDD on one of the plugs.

18-08-2010, 02:55 PM
Hi Daniel

do you know of a supplier, I've looked on maplins but can't seem to find any


18-08-2010, 03:21 PM
Something like this if you live near an RS shop:

Or this (closest match on eBay) with postage:
http://cgi.ebay.co.uk/1-x-10R-25W-Aluminium-clad-wirewound-Power-resistor-/130368440674?pt=UK_BOI_Electrical_Components_Suppl ies_ET

Dan :)