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Author Topic: Power supply on the Arduino UNO rev 3  (Read 339 times)
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Hi,
First of all, thanks for all these info and this fantastic prototyping plateform.
I've just received my first Arduino UNO rev3, so i'm a newbie

i've check lot of pages but i didn't find the answer...
Sorry if the answer has already be given.

So, my question is :
If i connect my computer to Arduino through the USB cable and i plug at the same time an expernal power supply, do the board still take the AC from the xternal plug or does it take it from the USB ? (as Arduino Uno switch automaticaly)

I'm asking you because a red that there are some risk to destroy the USB port if we use too much electricity from it...

Sorry for my bad english.

TBH
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hi,

Board is designed to automatically switch between external and USB power.
If you connect external power supply to Vin pin or DC Jack, than the board will automatically isolate the USB power from board. If you look the Arduino UNO schematic than you can see how the switch is work.

Rudolf
« Last Edit: December 31, 2013, 03:57:47 am by rudika79 » Logged

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Hi, the input socket is DC,do not apply AC to it.
I hope you mean that the adapter is an AC wall adapter and that it has DC output.

Tom.... smiley
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I'm asking you because a red that there are some risk to destroy the USB port if we use too much electricity from it...

Wrong.

USB ports will shut themselves down if you use to much. They recover when you remove the load. It's part of the USB specification.
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Hi
Definitively, it' DC and not AC... ;-)
And basically, it won't be a wall supplier but a Li-Ion battery.
So, if i well understand, i just need to plug the - to the GND and + to the Vin, is it correct ?
I've a Arduino Uno Rev3.
My battery is this one (as i red, maybe the tension is too low ?!) : http://www.sgbotic.com/index.php?dispatch=products.view&product_id=216
----
Ok, definitively, this battery can't suit the arduino as it's is only 3,7v
---

By the way, i've bought this chargeur. Do you know if it stops when the battery is full ?
http://www.sgbotic.com/index.php?dispatch=products.view&product_id=1000

Thanks again, i'm really a newbie.

TBH
« Last Edit: January 01, 2014, 05:45:40 am by TheBigHunt » Logged

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Quote
maybe the tension is too low ?!

Yes it's too low. As described here it should be 7-12VDC.
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Quote
maybe the tension is too low ?!

Yes it's too low. As described here it should be 7-12VDC.

Yes, thanks.
Ok, i'm going to buy a new one.
As soon as I get it, to connect it to the UNO, the (-) to the GND pin and the (+) to the Vin ?! Is it correct ?
Even if I connect the board to my computer in USB, the electricity used by the board will be the one from the battery ? Is it correct ?

Thanks
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I guess you need the battery so your project can be portable, mains free? Becasue if not, an easier solution is a say 9 or 12VDC wall adapter thingy with a 2.1mm centre-positive connector for the round socket.

For long-term battery use, I'd solder a 2.1mm plug onto the battery leads instead of using the Vin and Gnd holes.
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I guess you need the battery so your project can be portable, mains free? Becasue if not, an easier solution is a say 9 or 12VDC wall adapter thingy with a 2.1mm centre-positive connector for the round socket.

For long-term battery use, I'd solder a 2.1mm plug onto the battery leads instead of using the Vin and Gnd holes.

Yes, i found a 12V DC Wall adapter with the correct connector. It's a 1A. I guess that this 1A suit good for the Arduino Uno

Thanks for all

TBH
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Hi,

Quote
As soon as I get it, to connect it to the UNO, the (-) to the GND pin and the (+) to the Vin ?! Is it correct ?

Yes, it is correct.

Quote
Even if I connect the board to my computer in USB, the electricity used by the board will be the one from the battery ? Is it correct ?

Yes

Quote
Yes, i found a 12V DC Wall adapter with the correct connector. It's a 1A. I guess that this 1A suit good for the Arduino Uno

1A is more than enough. 

I don't know what is your project with Arduino, but you can use 9V Alkaline or rechargeable battery as well.

Rudolf
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