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Topic: Arduino Uno ext power + usb power failure (Read 779 times) previous topic - next topic


Hey everyone

I was in the believe that the Uno had "auto-switching" on ext power and usb power, so while it was on usb power I plugged in a 9V battery to the 2.1mm jack. That rendered my ext power input useless. It will not accept power from the plug, and as soon as I plug the battery in, the voltage drops from 9V to 2.5V across the battery.

It did work on battery prior to me plugging it in simultaneously.

Did I fry the voltage regulator?

regards Troels


Thats odd, it works again now.

Move along  8)

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