An AC adapter, also known as an AC/DC adapter, is an external power supply that converts alternating current (AC) from a wall outlet to direct current (DC) needed by an electronic device. It is often enclosed in a case similar to an AC plug and may be referred to by other names such as wall charger, power adapter, power brick, or wall wart. 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.
AC adapters come in different types, including wall mount and desk mount, and have different plug types, input and output voltages, and power ratings. Each AC adapter has a specific power rating, measured in volts or wattages that it can handle and output to an electronic device. It is important to choose the right AC adapter for your device by determining the electrical rating of the device and selecting a compatible third-party accessory if OEM adapters are no longer available from manufacturers. A universal AC adapter may be used if necessary, which is designed to work with many devices, having multiple types and sizes of plugs for connectivity to those devices.
