Power Brick

Also referred to as a transformer or POE (Power over ethernet), an element of the external power supply for a notebook and/or laptop computer, used in conjunction with a battery pack. Since notebook computers rely on low-voltage DC, they need a way to convert the AC from a power source into DC that can be safely used by the computer. The power brick takes the AC voltage and converts it to a DC voltage slightly higher than the battery (the slight elevation in voltage ensures that the battery stays fully charged). Batteries normally supply the safe DC voltage to the portable computer, but power bricks are intended for use in conjunction with or instead of a mobile device’s battery.