hello, i have due board , want power 9v powersupply, connects 5v regulator curcuit, again connects through vin pin on board. board built box , allow direct connection of 9v powersupply. can use 5v on vin pin or 3,3 v maximum? quote from: zenseidk on jun 20, 2014, 11:52 am hello, i have due board , want power 9v powersupply, connects 5v regulator curcuit, again connects through vin pin on board. board built box , allow direct connection of 9v powersupply. can use 5v on vin pin or 3,3 v maximum? vin . input voltage arduino board when it's using external power source (as opposed 5 volts usb connection or other regulated power source). can supply voltage through pin, or if supplying voltage via power jack, access through pin. 5v . pin outputs regulated 5v regulator on board. the board can supplied power either dc power jack (7 - 12v), usb connector (5v), or vin pin of board (7-12v) . supplying voltage via 5v or 3.3v pins bypasses regulator, , can damage b...