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Topic: ADC Nonlinear Output (Read 1 time) previous topic - next topic


Sounds like we need to know a lot more about the circuit - several opamps, not clear what values are getting to AREF, we don't really know what you were plotting against what and you haven't posted the code that prints out the analogRead() values - you have several unexplained constants in the code that might mean you are not printing out the straight output from analogRead() ??

In general it pays to post the whole code and the circuit, rather than describe them in words, saves a lot of guesswork and questioning.  The problem may not be where you think it is, thats often the nature of problems...
[ I won't respond to messages, use the forum please ]


Hi Everyone,

I apologize for not posting sooner. Last week I discovered the mistake lies on my end - I was getting a nonlinear output from the Arduino when I had my op-amp plugged into it because the op-amp was not powered  :~. I was tricked into thinking it was working since it would provide a nice linear output for the low end of the scale. The op amp is part of a larger power management board that I am working on, and I just forgot that I did not populate the jumper which would connect the 5V Arduino supply to the 5V rail of my power management board.

Thanks for replying to my post! It helps a lot just to say some things out loud to figure out a problem.



I used to use my wife for that before she passed on... frequently if you can hear your words you can find the error. BTW Cancer got her. not terminal boredom from my infrequent... Monologs.

--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

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