output voltage wrong when powering a mega from Vin pins

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What steps will reproduce the problem?
1. Give power to the arduino mega over the Vin and GND Pins, I provided a 
stable 5V to there.

What is the expected output? What do you see instead?
I expected that the digital out's in high state and other pins with a 5v 
marking would be at 5 Volts. But they were at 4,00-4,16 Volts

What version of the Arduino software are you using? On what operating
system?  Which Arduino board are you using?

It has nothing to do with what software I am running. Totally a hardware thing. 
But since you wanted it: the arduino soft is 0021 and I am using BackTrack 4 
(linux) and the board is Arduino Mega.

Additional info. I also tested this against the updated Mega, and the problem 
still exists.

Original issue reported on code.google.com by karul...@gmail.com on 19 Oct 2010 at 10:38

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This sounds like more of an issue for the forums, but...

The problem sounds like you're applying the 5V input in the wrong place. Going 
through Vin, the voltage would be regulated by the Arduino's 5V regulator. 
Because of the limitations of the regulator, you need to feed it at least 6V to 
get a nice, stable 5V output.

If you want to use your own externally-regulated 5V source, you should connect 
it to the 5V pin, not Vin.

Original comment by picxp...@hotmail.com on 19 Oct 2010 at 3:46

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Original comment by dmel...@gmail.com on 19 Oct 2010 at 5:29

• Changed state: Invalid