What type of resistor is needed for a dummy load on a 350W PC PSU?

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SUMMARY

To create a dummy load for a 350W PC power supply unit (PSU) with 3.3V, 5V, and 12V outputs, a 10-ohm, 10W resistor is recommended. Users should check the PSU's datasheet for minimum output current requirements for each rail. It is confirmed that grounding the Power On line allows the PSU to operate correctly. A user successfully implemented a 6.8-ohm, 10W resistor connected to the 5V output, enabling the PSU to turn on and off with a switch.

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  • Knowledge of electrical resistance and Ohm's law
  • Familiarity with wiring and connecting components in electronic circuits
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Glenn Borg
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Hi,
I have a 350 w PSU (PC) with 3.3, 5 and 12 v outputs.

I want to create a dummy load so that i will remain on and output the correct voltage.

However, i found online that a 10 ohm 10w resistor is needed such as this one :
http://www.fabian.com.mt/en/product...tor-wirewound-aluminium-housed-10-ohm-10w.htm

Can you kindly verify if i need one for every output ? (3.3, 5 and 12 v)
Or i connect one end to a Positive 5v and on the other end ground and still can use all outputs ?

Thanks
 
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Glenn Borg said:
Hi,
I have a 350 w PSU (PC) with 3.3, 5 and 12 v outputs.

I want to create a dummy load so that i will remain on and output the correct voltage.

However, i found online that a 10 ohm 10w resistor is needed such as this one :
http://www.fabian.com.mt/en/product...tor-wirewound-aluminium-housed-10-ohm-10w.htm

Can you kindly verify if i need one for every output ? (3.3, 5 and 12 v)
Or i connect one end to a Positive 5v and on the other end ground and still can use all outputs ?

Thanks
PC power supplies often have a minimum output current on one or more of the rails. The datasheet for the power supply should specify those minimum output currents -- have you checked for that yet?
 
Glenn Borg said:
Can you kindly verify if i need one for every output ? (3.3, 5 and 12 v)
Or i connect one end to a Positive 5v and on the other end ground and still can use all outputs ?

berkeman said:
PC power supplies often have a minimum output current on one or more of the rails. The datasheet for the power supply should specify those minimum output currents -- have you checked for that yet?

agree with Berkeman, there are those that are like that
and a large majority have a Power On line that needs to be grounded before the PSU will start up and run

ATX power pins.JPG


just permanently ground the Power On line and the PSU should always start up and supply all railsDave
 
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Thanks a lot for the answers, i have managed to install a resistor (6.8 ohms 10w) connected to a 5v output. managed to turn on with a switch on the green wire and ground. so far so good, switches on and off accordingly. Thanks
 
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Likes   Reactions: davenn and berkeman

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