An uninterruptible power supply (UPS) is used to protect critical loads from utility-supplied power problems, including spikes, brownouts, fluctuations and power outages, all using a dedicated battery.

There are three basic functions that it essentially performs:

• avoids damage to hardware caused by overcurrents and voltage spikes. Many UPS models also continuously regulate the input power.
• avoids data loss and damage. In fact, without a UPS, data stored on devices subject to sudden shutdowns can be corrupted or completely lost. If a power management software is also used, the UPS allows and facilitates the controlled shutdown of the system.
• ensures the availability of networks and other applications while avoiding downtime. When used in conjunction with power generators, ensure that they have enough time to ignite in the event of a power failure.