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Topic: Power Supply For Arduino (Read 596 times) previous topic - next topic

NobleNoob

Oct 16, 2012, 12:11 am Last Edit: Oct 16, 2012, 12:20 am by NobleNoob Reason: 1
Can an Arduino 2560 run comfortably at a regulated 12V?

I would like to power my projects with a converted ATX power supply and power the Mega from the 12V rail.

Or do I need to step it down to 9V

I read somewhere the upper voltage limit was 12V

Dropping to 9V adds more components, cost, failure points to my project.

Thanks In advance....

johnwasser

If your ATX power supply has regulated 5V you can connect that to the +5V pin.

The regulator on the Arduino can deal with voltages up to about 18V, if I recall correctly.   At 12V the regulator is dumping 7/12ths of the power as heat so it tends to get very hot.
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NobleNoob

#2
Oct 16, 2012, 04:21 am Last Edit: Oct 16, 2012, 04:26 am by NobleNoob Reason: 1
I thought I read somewhere that the minimum voltage should be 6.35 volts to correctly operate the integrated reglulator.

Given that you must obviously know what you are talking about, I must assume that you were talking about making the 5V supply connection to the 5V Pin instead of the dc power jack and I further assume that the 5V Pin does not use the integrated regulator?

Is this correct?

by connecting this manner will I still have 3.3V?



CrossRoads

Don't supply 5V to the 5V pin witout adding a diode from there to the Vin pin.  Apparently the latest regulators are sensitive to being reverse driven.
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

johnwasser


I must assume that you were talking about making the 5V supply connection to the 5V Pin instead of the dc power jack and I further assume that the 5V Pin does not use the integrated regulator?

Is this correct?


That is correct.  That's why I said "If your ATX power supply has regulated 5V you can connect that to the +5V pin." :)

The problem of the regulator being sensitive to reverse voltage is news to me but CrossRoads is a trained electronics engineer so I trust his statement.
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