UPS ? Un-interrupted Power Supply  

UPS consist of a battery system that maintain power in the event of power failure. It typically keeps power running for several minutes after power failure which is critical time to save unsaved data on computers, and shut it down properly till power is back on. Many UPSs now offer a software component that enables backup and shut down procedures if the computer is not attended. There are two basic types of UPS systems:
? Standby power systems (SPSs)
? On-line UPS systems.
An SPS monitors the power line and switches to battery power if it detects an power irregular problems.
The switch to battery, however, can require several milliseconds, during which time the computer is not receiving any power.
Standby Power Systems are sometimes called Line-interactive UPS. An on-line UPSs that can avoids these momentary power lapses by constantly providing power from its own inverter, even when the power line is functioning properly. In general, on-line UPSs are much more expensive than SPSs