It is used to protect sensitive devices from sudden power outages,that varies according to the capacity of the battery attached to the UPS.
There are many protections inside the UPS device, the most important of which is protection against high and low voltage, which directly affects the performance of the devices, and works to stabilize the output electricity.

The internal components of a UPS: 
- The first part: in which alternating current is converted into direct current.
- The second part: in which continuous current is used to charge a number of batteries.
- The third part: the direct current coming from the battery is converted back to alternating current.
When the power is cut off from the loads, the UPS device will continue to feed the loads from the battery, but within a limited period determined by the capacity of the battery and the amount of current drawn from it.

Choose the appropriate UPS device:
The appropriate choice is made based on the two most important elements that must be specified in the UPS specifications when purchasing them:
- power factor 0.6
-The value of the maximum current that can be fed.
- The maximum duration of such feeding
The greater the current and the longer the duration, the larger the size of the UPS and the higher its price. Mostly we need this device for a short period, and during the short period the charge stored in the UPS batteries is the only source of nutrition until an external electric generator is turned on until the battery is charged again.

Uses of the UPS device:
- Protect computers and laptops
- Security cameras protection
- Protect corporate servers.