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### Topic: Current Consumption in Ardunio Mega (Read 2295 times)previous topic - next topic

#### Vik009

##### May 03, 2012, 01:02 pm
Hi,

I wanted to know how much current is consumed by Arduino Mega in normal mode. Has there been any project for power consumption with Arduino Mega ?

BR,
Vik

#### johnwasser

#1
##### May 03, 2012, 06:15 pm
The Arduino Mega draws about 60 mA when you power it from 12V through the built-in regulator.  Much of that power is lost in the regulator.
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#### Grumpy_Mike

#2
##### May 03, 2012, 06:24 pm
Yes but I would expect that it takes 60mA no matter how you power it.

#### permnoob

#3
##### May 03, 2012, 06:42 pm
yes, and if it is drawing 500 ma, there may be an issue.  ask me how i know...

#4
how do you know?

#### johnwasser

#5
##### May 04, 2012, 02:32 pm

Yes but I would expect that it takes 60mA no matter how you power it.

I think I understand.  At 5V it would be drawing 60 mA (0.3 Watts). at 10V it would be drawing 60 mA (0.6 Watts) and at 12V it would be drawing 60 mA (0.72 Watts).  Same current, more wattage.  With the additional wattage being dissipated as heat in the regulator?
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#### Grumpy_Mike

#6
##### May 04, 2012, 05:00 pm
Quote
With the additional wattage being dissipated as heat in the regulator?

Yes that's it.

#### permnoob

#7
##### May 04, 2012, 08:02 pm
yes, and I have done some rough calculations on heat dissapation for the voltage regulator on the R3 board.  my numbers are here for you folks, and understand I AM NOT AN ELECTRICAL ENGINEER so verify my info.

.79 watts is the max power you want to run through that thing and feel very safe

based on the npc1117 regulator, even tho the ic says RVB 117 5
Code: [Select]
`ambient temp 50c (remember a hot IC heats the air around it, and I don't have a fan on mine!)max IC temp 125 c (150 is abs rated max, 175 is thermal shutdown)pad size 11x11mm (this is conservative, as i don't konw the copper weight, i am ignoring the bottom pad because vias do not conduct heat too well, the actuall top pad is about 10.8x8.1mm, bottom is 10.8x17.5)this gives a 95CW thermal resistance(125C-50C)/95(CW)=.79 Wor 66mA @ 12 v113 mA @ 7 v`

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