# Quick Question on resistor for a power supply



## Death Wraith (Mar 23, 2006)

I'm looking to hack a power supply as done on this site:

http://web2.murraystate.edu/andy.batts/ps/powersupply.htm

They specify a 10 oHM, 10 WATT resistor to provide a load so the supply will work. I've done this hack successfully before but now I don't have access to this particular resistor. I'm putting together an order from AllElectronics and they don't have a resistor with those specs. What can I use as a substitute? 20 Ohm, 10 watts?? 10 Ohm, 20 Watts?? What spec can I change and still have it work and be safe??

Thanks for any answers!!

DW


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## heresjohnny (Feb 15, 2006)

Death Wraith said:


> I'm looking to hack a power supply as done on this site:
> 
> http://web2.murraystate.edu/andy.batts/ps/powersupply.htm
> 
> ...


Stick with the 10 ohms, and a power rating that is equal to or higher than 10 Watts. So the 10 ohm, 20 watt resistor would work.


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## Otaku (Dec 3, 2004)

HJ is correct, but R/S has a 10 ohm, 10 watt power resistor.

http://www.radioshack.com/product/i...+Type/Power+Resistors&fbc=1&parentPage=family


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## Death Wraith (Mar 23, 2006)

Thanks so much to both! I'll check out RS..

DW


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## Liam (Mar 23, 2007)

That's funny, I was actually searching for exactly this sort of setup to power my LED spotlights this year. I have run out of those good old AT power supplies, so am stuck using ATX, which is obviously much less user friendly.

Anyway, check out the bottom of the page. There's a "Resistor Substitute" section that will probably help enormously. "A viable alternative to using a power resistor is to substitute an 1157 automotive signal lamp in its place."

Hope that helps!

Liam


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## Hellspawn (Oct 13, 2006)

Wow, I must be lucky, I ripped apart 4 old power supplies and they worked without the need of a load.

mabey there are specific power supplies that dont need a load to run?


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## Death Wraith (Mar 23, 2006)

I know nothing about electronics (so why am I fudging around inside a power supply????). LOL Anyway I don't know about your luck HS. Maybe older supplies?? I know the one that I first hacked wouldn't turn on until I wired in a resistor.

DW


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## MansionHaunter (Sep 20, 2006)

The type of power supply discussed in the link is a switching power supply. It has to have a load of some sort in order to properly supply the intended voltage.

A linear power supply doesn't necessairly need a load. This is the kind with a transformer, rectifier and capacitors. As soon as you add a voltage regulator of some kind, it requires a load in order to operate properly. 

Question is, what are you trying to run?


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