Wiring an 2 DC Barrel Jack - forumino forumino››Wiring an 2 DC Barrel JackMar 15, 2012Wiring an 2 DC Barrel Jack. Arduino Forum > Using Arduino > General Electronics > As used in an Arduino: or battery. The adapter can be connected by plugging a 2 center-positive plug into the board's power jack. Leads from a battery can be inserted in the Gnd and Vin pin headers of the POWER connector. Power Jack & Supply | Ladyada's Learn Arduino - Lesson #0 DC Power Jack. There are two ways to power your Arduino: you can use the USB connector to connect to a computer or portable power pack or you can plug into a wall adapter. USB can be used to power and program. DC can only be used for power - but it's great for when you want to connect your Arduino and leave it plugged in for a long term project.