Uninterruptible power supply (UPS)

A device that allows your computer to keep running for at least a short time when the primary power source is lost. A UPS may also provide protection from power surges. A UPS contains a battery that "kicks in" when the device senses a loss of power from the primary source allowing the user time to save any data they are working on and to exit before the secondary power source (the battery) runs out. When power surges occur, a UPS intercepts the surge so that it doesn't damage your computer.