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 a direct current (DC) needed by an electronic device. It is a type of AC/DC converter that is used with devices that run on batteries or have no other power source. AC adapters are also known as wall chargers, power adapters, power bricks, and wall warts. They 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. Originally, most AC/DC adapters were linear power supplies, containing a transformer to convert the mains electricity voltage to a lower voltage, a rectifier to convert it to pulsating DC, and a filter to smooth the pulsating waveform to DC, with residual ripple variations small enough to leave the powered device unaffected.
Each AC adapter has a specific power rating, measured in volts or wattages that it can handle and output to an electronic device. The unit for voltage is volt (V), while current ratings end in amps or ampere (A) . Before picking the right AC adapter for your device, it is useful to know the reasons most portable electronics use external power adapters. In some cases, OEM adapters are no longer available from manufacturers. Therefore, finding the right AC adapter for your electronics requires selecting a compatible third-party accessory.
