Related power question. My board has a 4 pin female header which reads/looks like:
POWER
5V Gnd 9V
x x x xI've read the admonitions about not using too high a voltage or reversing polarity--so just want to be 100% sure this means I can use, for instance, a 9V battery to power the whole board. I've looked at the schematic for the board, which shows a VIN but doesn't specify a voltage. So, a related question for my general education is am I missing something on the schematic? Should I be able to definitively answer this question for myself?
Thanks!
Plug the 9V battery in via the external power connector, that way it is regulated by the 7805 down to the required 5V.
You can sort of answer the question for yourself - the first component after the plug is the 7805 regulator, so the arduino board's input voltage range is defined by the allowable voltage range of the 7805 - and you can find this in it's datasheet.