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. Adapters for battery-powered equipment may be described as
chargers or
rechargers (see also
battery charger). AC adapters are used with electrical devices that require power but do not contain internal components to derive the required voltage and power from
mains power. The internal circuitry of an external power supply is very similar to the design that would be used for a built-in or internal supply.