9V 3A Power Supply Adapter
9V 3A Power Supply Adapter in pakistan BR1444The short answer is: 9 to 12V DC, 250mA or more, 2.1mm plug, centre pin positive. The long answer is that an off-the shelf Arduino adapter: must be a DC adapter (i.e. it has to put out DC, not AC); should be between 9V and 12V DC (see note below); must have a 2.1mm power plug on the Arduino end, and the plug must be "centre positive", that is, the middle pin of the plug has to be the + connection. Here's a picture of an adapter ideally suited to powering the Arduino. An AC adapter, AC/DC adapter, or AC/DC converter is a type of external power supply, often enclosed in a case similar to an AC plug. Other common names include plug pack, plug-in adapter, adapter block, domestic mains adapter, line power adapter, wall wart, power brick, and power adapter.