I just picked up a 12vdc 2A power supply (wall wort type). It reads 12.46vdc on my multimeter when plugged in but with nothing connected. Can I use this on the arduino uno or should I only use it on the motor shield after cutting the Vin trace on the bottom of the motor shield? (Still waiting for the motor shield to arrive from China.) Dave
the arduino can handle up to 20Vdc, but the voltage regulator will get hot. safe range is arround 7 - 12Vdc. just make sure NOT to connect it to any pin other than Vin (or the barrel jack), and of course, ground to ground. See technical specs at https://www.arduino.cc/en/Main/ArduinoBoardUno. ~Travis
