Hopefully this is not too stupid of a question , the Funduino that I am using is both powered and programmed by its USB port. What harm if any would occur if I use the aux 3.5 mm power input jack and have the USB plugged into the computer while programming .I am under the impression that while there is no advantage other than a higher amperage availability by using the power input jack that this should still work ok without damaging the board because it has its own voltage regulator. Any possibilities that it could harm the board or worse yet the laptop I am using?Thanks
You have two different potentials supplying the same board. Best case, nothing happens. Worst case, you fry something.
Its bad practice to mix potentials, because you create a "floating" voltage of 1.5v between the two. For many electronics projects this is bad juju.
Will it damage your board? I've no idea. Could it damage it? Certainly.