What is a Power Brick?
(pow &r brik) (n.) Also referred to as a transformer, 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.
Note Well: Unlike power supplies and voltage regulators for desktop computers, those for portable computers do not conform to any industry standards, so power bricks are not necessarily interchangeable among portable devices.