AC adapter

An AC adapter or AC/DC adapter (also called a wall charger, power adapter, power brick, or wall wart)^[1] is a type of external power supply, often enclosed in a case similar to an AC plug.^[2] AC adapters deliver electric power to devices that lack internal components to draw voltage and power from mains power themselves. The internal circuitry of an external power supply is often very similar to the design that would be used for a built-in or internal supply.

When used with battery-powered equipment, adapters typically charge the battery as well as powering the equipment.

Aside from obviating the need for internal power supplies, adapters offer flexibility: a device can draw power from 120 VAC or 230 VAC mains, vehicle battery, or aircraft battery, just by using different adapters. Safety can be another advantage, as hazardous 120 or 240 volt mains power is transformed to a lower, safer voltage at the wall outlet before going into the appliance handled by the user.