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For some reason, my 3.3v on my Arduino is fluctuating a lot, and I am not sure why. The multimeter is measuring dc voltage and is connected between GND and 3.3v of an Arduino Mega.

The multimeter works fine. Connecting between 5v and GND gives 5V on multimeter.

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    the video is meaningless ... it does not show what you are measuring
    – jsotola
    Feb 29 '20 at 5:08
  • Im measuring DC voltage between gnd and 3.3v Feb 29 '20 at 5:09
  • @jsotola can you tell me what information I should include? Feb 29 '20 at 6:59
  • you have to disconnect everything from the board, upload a blank sketch and measure it again. Feb 29 '20 at 8:01
  • Tried that still fluctuated Feb 29 '20 at 8:05
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Arduino output voltages may "fluctuate" a few mV but what you showing us in that gif is really unstable.

What you should be doing is:

  1. Disconnect everything from Arduino except the power source
  2. measure the voltage again;

Is it stable? the problem was because of pulling too much current that causing voltage drop and instability .

Is it unstable?

  1. Try checking with another MM and/or change auto-range to manual.

Is it stable when measuring the voltage with another MM? something was wrong with your previous MM.

Still unstable?

  1. Connect the Arduino to a 9V power adapter and disconnect the USB cable.

Measure the voltage again, if it's stable the problem was because of some error in the cable or USB power source.

Voltage is still unstable?

  1. change the 3.3V voltage regulator.

It should fix the problem if not report back to do some more in-depth problem solving.

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  • My voltage Reg was off I should have tested before asking, but thanks! Mar 1 '20 at 6:26
  • 1
    @SanjitSarda Just for my curiosity, what do you mean with "my voltage reg was off"? Was it broken or did you switched it off. If you switched it off, how did you do that? Mar 1 '20 at 10:43

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