understanding currents safe for arduino uno

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firobug
 
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Joined: Sat Jul 05, 2014 9:43 am

understanding currents safe for arduino uno

Post by firobug »

i am trying to understand how to know what power limits are safe to run the uno at. i know it says it needs a +5v supply but how much more it can handle is unclear it comes with a 9v reccomended attachment but most 9v that i see only have about 700milliamp.....im not sure if it would be safe to hook it up to say a laptop power supply at 19v apx 6 amps or maybe more likely my 8 cell AA battery clip from radioshack that has the 9v supply...with that i figure im pushing anywhere between 12v and about 9.6v at a peak load of roughly 3.5 amps if im running my rechargables and i know they tend to pulsate when they reach lower amperage thanks to led flashlights....if thats not due to the circuitry for the lamp...im under the understanding that the circuitry resistance does come into play when calculating voltage somehow but am new to this whole thing and i couldnt quite figure out what exactly i am supposed to do to factor everything in....i mean ok resister resists xxxxx milliamps or is that microamps....or fractions of a volt.......and im supposed to what factor a degree of resistances on each circuit to ballance out multiple tasks so like if i have some 12v motors im trying to run in a circuit along side of using a wireless control shield which presumably calls for 9v i would have to redirect the circuit to burn off that extra power before reaching the the system....and these leads are powering the chip right which is a complete circuit feeding these leads so obviously it has its own independent threshold.....please help me out here cause i am really new to all this but want to be a maker so im making my effort.....maybe i could really use a chance to sit down and talk to a person who has been using this platform for some time to really be able to understand things fully you can contact me at [email protected] if you would please and then i could give out my number...thanks for any help

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adafruit_support_rick
 
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Re: understanding currents safe for arduino uno

Post by adafruit_support_rick »

The Arduino will only draw as much current as it needs. A 9V 700mA supply is fine. Higher amperage is also fine. The important number is the Volts. The arduino needs at least 7V at the barrel jack , due to dropout in the voltage regulator.

Although Arduino says that a Uno will run on up to 20V, that really puts too much stress on the voltage regulator and is not recommended. The recommended max input is 12V.

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