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Old 06-10-2003, 07:31 AM   #1
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Default Converting Computer Power Supply. Resistors Q's

when i went down to the elctronics store to pick up some 25 watt x 8ohm resistors they said you have to special order them. but then they said that they get really really hot and you need to put heat sinks on them.

do i really need to put heat sinks on them?
http://www.magicookie.com/prodigy/psupply.htm
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Old 06-10-2003, 10:18 AM   #2
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It' depend on what kind of the Resistor you ordered.

You do not need a heatsink if your using chassis mount type Resistors.



With this type of Resistor... you mount on the chassis, so the chassis will become part of Resistor's heatsink..
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Old 06-10-2003, 11:33 AM   #3
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im using somethign like this
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File Type: jpg power%20supply%20conversion%20012.jpg (15.4 KB, 588 views)
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Old 06-10-2003, 07:31 PM   #4
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From the photo, I saw a bunch of a Resistor ceramic type parallel together. By parallel them Resistors together the resistance goes down but the wattage goes up.

For example, if you parallel 2 of an 8Ohm 25Watts together. The Resistance value will be 4Ohm 50Watts.

Without seeing the schematic I can’t really tell you how much current or voltage those Resistors will be handled. I guess you will have to “feel” it when you power it up with a LOAD.

Just make sure the schematic or the instruction called for 1 each 8Ohm 25Watts or a # of 8Ohm 25Watts parallel together.
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Old 06-12-2003, 03:29 AM   #5
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I've done it like komkit and Calvin NG. It've worked fine for approx 3/4 year. I've placed the resistors right in front of the fan, that help a lot in keeping the temperature down.
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Old 06-12-2003, 04:00 AM   #6
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i use a 1 ohm resistor, 10, and a 20 and it gives about 13.4 volts
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Old 06-12-2003, 04:10 AM   #7
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The PC-PS in the Magicookie article is an "AT" PSU right, not an "ATX"??
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Old 06-12-2003, 05:11 AM   #8
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I never used the PC's pwr supply conversion before.

I just used one of this... and be done with it worry free.



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Old 06-12-2003, 06:14 AM   #9
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my PSU is 250 watt

and i reckon it could handle 15 amps
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Old 06-12-2003, 07:24 AM   #10
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i live in edmonton, alberta canada

does anyone else???

i cant find resistors with 25watt 8ohm
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Old 06-12-2003, 06:22 PM   #11
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now i have a capacitor question for the power supply

what kind of voltage should i be looking for with the caps?
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Old 06-12-2003, 11:39 PM   #12
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anything about 16 volts
a capacitor that is rated at 25 volts will do the same job as a 16 volts capacitor

but dont go under your output voltage.
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Old 02-19-2005, 08:47 PM   #13
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does anyone noe of any other sites that has more pics?
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