An AC Power Adapter is an electronic device which produces a specific direct current from the mains with an Alternating Current (AC). Although actually a power supply it is popularly known as an AC Power Adapter or AC Adapter. Laptops along with most other portable devices use Direct Current(DC), this also applies to rechargeable batteries which power laptops. Direct Current has a constant flow of electric charge in one direction and flows from low to high potential. Connecting a laptop to AC is unsuitable and dangerous due to the varying magnitude and direction of the current, which can cause an internal component to fail and even result in fire. The AC Adapter carries out the following steps to produce the correct current and voltage to power your laptop or charge your laptop battery:

•Converts the mains voltage to a lower voltage level

•Converts the AC voltage to a DC voltage by a process called rectification

•Smooths out any voltage ripple

•Converts the voltage to the required voltage to power the laptop

The other well-known name for an AC Power Adapter is battery charger or laptop battery charger. This is an important device providing you with laptop mobility and frees you of restriction from using the power cord.

This is a particular design of a power adapter which accepts DC input and output DC voltage required to power a laptop. Instead of a standard plug for a wall socket, these have a specific cable that plugs in the cigarette lighter. The 12V DC supplied through the cigarette lighter socket is converted to provide a different DC voltage. This power adapter can also be used in other vehicles with similar sockets i.e. Vans, trucks and even boats. Air or airplane adapters work in the same way.

Complying with most mains power supplies worldwide, a universal power adapter or power supply is able to accept an input voltage ranging from 100 - 240 V with a frequency range of 50 - 60Hz. A truly universal product. However, the term universal also applies to the array of laptops it can supply power to. Laptops are built to various specifications and the power consumption varies accordingly. Physical attributes also differ between laptops and are not limited to the power socket. Manufacturers of universal laptop power adapters supply various connecting tips allowing the adapter to be connected to various laptops. These connecting tips help the power adapter detect the correct voltage to supply the laptop.

Universal power adapters are also available for cars and airplanes. Supplied with different types of plugs to fit a car cigarette lighter socket or the in-seat adapter on most airplanes, such power adapters truly allow the user to be mobile over great distances. The 2-Power Universal Car Air Power Adapter can power 98% of laptop computers.