Power supply for breadboard

Hey I'm going to convert this cpu supply with just lugs for each 3.3, 5, 12: http://www.apextechusa.com/datasheet/ATX450W.pdf

Whats the best way to make sure i don't dry my uno?

Do you have Health Care ? (and Safety Glasses ?) (Have you written your last will and testament ?)

Don't use that supply. It is way over rated.

[u]3.3V @ 28A[/u] If you powered any 3.3v circuits with this and miswired something , your chips would literally explode .

[u]5V @ 50A[/u]

Same problem. The power supply can source way too much current.

Last option, [u]If and only if[/u] the PS 3.3V COMMON is isolated from the 12V COMMON, you can connect the two commons together and take the output from the two + output pins , using the 3.3V + pin as your GND and the 12v + pin as your positive, and you should get 12V-3.3V = 8.7V dc which is perfect as an input voltage for the Arduino external dc barreljack (the Vin pin). The arduino 5V regulator would provide your protection because it would shutdown if there was a short across the 5V lines. Your CPU ps on the otherhand will source what it is rated so you can't safely use it directly because one miswire and your breadboard would explode sending chip fragments everywhere and then catching fire. You would be much better off just buying a 9V walwart to power the arduino external dc barreljack.

Yes. I have an ATX power supply that I've modified and fitted terminal posts to. It's very useful for things like electroplating or running motors but I wouldn't let it anywhere near an Arduino!


Eh, an ATX PSU is maybe not ideal, but perfectly serviceable as a breadboard supply if nothing else is available. Fuses, people! Pick a power supply line and use regulators. Your basic 78XX is a decent enough current limiter.

I would use in line fuses rated about 1A for the 5V power. If you plan to use the external dc barreljack you should use a 7809 . The onboard 5V regulator will run hot if you use 12V on the external dc barreljack. The 3.3V should probably be fused at 3/4 A. (0.75A)

Once saw a guy try to magnetize a big screwdriver by wrapping 6 turns of battery cable around the shaft then sticking the ends across a 12 volt car battery, I guess the filler caps are still in low orbit.

I guess the filler caps are still in low orbit.

Battery acid is not very user friendly...

The occasional spark is part of the fun :) At work there was a mechanic who accidentally dropped an O-ring between the main terminals of an aircraft battery, on the inside of the case. Couldn't reach it with his fingers, so he decided to fish it out with his calipers. Short circuit current of a 40308 main battery? In the neighborhood of 40KA. Never before have calipers so radically changed shape so fast. He won't be trying that again.