The Full form of UPS is Uninterruptible Power Supply. UPS is a source of power supply system that’s having an inbuilt battery and that battery is used to supply power in the absence of primary source or when supply is cut off. An UPS can easily keep a computer running for some minutes giving you enough time to save all your data in order not to lose it. So, battery size is an important factor in the selection of UPS systems. At Present, there are many UPSs in the market that offers software which automatically saves your data and shut down your computer. The UPS works as mediator or as a connector between the general supply and the device using the UPS. There are two types of UPS system, one is Stand-by power system and other is Online UPS. Stand-by power system is also called offline UPS and switches to battery in few milliseconds when the power is cut off. This supply is mostly used in a computer or office supply store. Online UPS supplies uninterrupted power from its own inverter. It has two drawbacks, first one is that it is more costly as compared to the stand-by UPS and other one is that it creates a lot of noise as it contain cooling fan.