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Author Topic: Using an ATX power supply  (Read 3420 times)
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The biggest problem with such a supply is the fact that without modification (not an easy task unless you have a schematic for the supply and are an "expert" in power supply design) you can't set a current limit for a given voltage.

I'm wondering about this though, can't I just stick a current limiter in front of the component?
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The biggest problem with such a supply is the fact that without modification (not an easy task unless you have a schematic for the supply and are an "expert" in power supply design) you can't set a current limit for a given voltage.

I'm wondering about this though, can't I just stick a current limiter in front of the component?


Yeah - you probably could; but at a certain point you're going to end up with a "franken-psu" and will probably spend as much money (in time, if nothing else) building it, and ending up with a less capable device than if you had simple purchased a bench PSU. Then again, you will have likely learned a lot by doing so, so you could factor that in. What is your goal? A power supply for your projects that will be reliable and accurate, and safe; or is it to learn how power supplies work and how to build them?
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.... What is your goal? A power supply for your projects that will be reliable and accurate, and safe; or is it to learn how power supplies work and how to build them?

You made the point: For sure it's more expensive (mainly if you calculate the time) to build it yourself (but
don't tell it my wife, please smiley-cool), and you end up with something not so performant than the same thing out of the box, but the reason why I'm playing with the Arduino is that I love the learning effect, and I have to admit that most of my projects becomes boring, just when they are finished.    The journey is the reward.


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I totally agree with all you ... my adapted PSU is pure shit, and I have expend several weeks simply trying to understand how a switching power supply works (and more specifically a PC one) ... but I have learn a lot!! :-)
(and I'm quite pride of my Frankistein!)

 smiley-cool
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This article may be of some interest.
http://www.pavouk.org/hw/en_atxps.html

This is the circuit of a common ATX power supply.
It uses a TL494 switcher chip which was / still is a very common control chip for these types of power supplies.
As long as the power supply you wish to convert has this chip or a similar one , irs pretty easy to make the output adjustable.
The 5V and 12V rails are regulated, but as there is only main transformer the outputs of the 2 rails are not totally independant.
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