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ATX Variable power supply. Answered

In the various instructables on this subject, all the component values aren"t given. such as the  120ohm resistor required but no watt value is given.
can anyone give me a detailed parts list so I can buy the components needed for this project?

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orksecurity
orksecurity

Best Answer 10 years ago

Generally, if the author didn't specify this, a 1/4 watt to 1/2 watt resistor will do the job. If there's a photo of the part, you can probably figure this out from its size.

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AndyGadget
AndyGadget

10 years ago

If that's across the 12V rail the current through the resistor will be 12 / 120 = 0.1A, so the power dissipated will be 12 * 0.1 = 1.2W.
Use a 2W resistor (or higher) and you'll be fine.

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Re-design
Re-design

10 years ago

If it's the 120 ohm resistor in this diagram that's connected to the voltage regulator control line, almost no current is carried thru it so a 1/4 watt would be fine.

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Re-design
Re-design

10 years ago

Which instrucable are you looking at???

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pollock9131
pollock9131

Answer 10 years ago

I'm going to have to shut my computer down now, It's storming real bad here. Thanks in advance for any help anyone can give! I'll check back in the morrning, for any further answers.

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pollock9131
pollock9131

Answer 10 years ago

Convert a computer power supply to a variable bench top lab power supply is the main one, but I've looked at others related to this as well. Some on WikiHow, "How to add variable voltage to your ATX based bench power supply. I greatly appreciate any help! Brand new to electronics but very interested and eager to learn!