UPS stands for Uninterruptible Power Supply A UPS provides constant electrical power to a given load for a specific period of time protecting against some of or all of the following power problems > Power failure / loss > Power Sags & Brownouts > Power Surges & Spikes > Line Noise > Frequency Variation > Switching Transients > Harmonic Distortion It does this by Supplying alternate power in the event of a power failure and by filtering and regulating mains power to remove any impurities