An Uninterruptible Power Supply is a device that sits between a power supply and a device to prevent undesired features of the power source from the supply from adversely affecting the performance of the device.

How do you pronounce "UPS"?

Many pronounce it "ups", but most of the literature seems to favor "you pee ess", since they use "a UPS" instead of "an UPS". This document will try to follow the literature. Neither pronunciation will get you laughed at by those who are experienced in the field.

How can it help me?

A UPS has internal batteries to guarantee that continuous power is provided to the equipment even if the power source stops providing power. Of course the UPS can only provide power for a while, typically a few minutes, but that is often enough to ride out power company glitches or short outages. Even if the outage is longer than the battery lifetime of the UPS, this provides the opportunity to execute an orderly shutdown of the equipment.