So, what is a UPS and why do I need one?

To understand why you need a UPS we need to tell you a little bit about electrical power. We all know what a blackout is -- a sudden loss of mains (AC) power. But equally dangerous are some things you may be less familiar with, such as spikes, surges, brownouts and blackouts. These terms all have to do with either too much power or too little. Either condition is bad for your systems, and can be prevented by a properly sized UPS. A UPS, in its simplest form, is a battery backup that takes over supplying electricity to your systems in the event of a power loss. Usually, a UPS is a separate box that sits in the power chain between the source of power (eg, a standard power point) and the rest of your systems. The UPS protects every other piece of equipment that is plugged into it. It is designed to prevent spikes, surges, sags and blackouts from reaching your valuable equipment (See "Power Problems" below). Being first in line, the UPS receives electrical current directly from the power outlet. When mains power is present, the UPS provides filtering (frequency regulation) of small fluctuations to ensure that a continuous supply of "clean" power is fed through to your equipment. When AC power fails, the unit uses its internal battery to supply back-up power without interruption. A typical UPS will power your system for 15-30 minutes, depending on its size (capacity) and the amount of equipment connected to it. Many, if not most, blackouts last for under one hour and while a good UPS will give you enough power to gracefully shut of your equipment during the first few minutes of the blackout, a more powerful unit can give you a "run time" long enough to ride through the entire outage. This will cost you more, of course, and you will have to plan your battery capacity appropriately. Some larger units can take extra battery packs to increase their run time.

PC peril

Without UPS protection, a sudden loss of power turns off everything, instantly -- often with disastrous results. Computers, in particular, don't like to just "have their plug pulled" with no warning. When you tell your computer to shutdown, it executes a series of commands that puts everything away in its rightful place, ready for the computer to be booted up again. It saves any open files or reminds you to do so, then deletes any temporary files that have been in use and are no longer needed. This usually takes only a matter of seconds, but it is vital to the health of your PC. Failing to shutdown properly like this can corrupt data files instantly. But that is only half the story. Giving your electronic equipment too much power can actually "fry" its insides. This power surge gives your systems a burst of more current than they can cope with, and they can burn out -- this can include your not only your internal power supply unit (PSU) but also your computer's memory (RAM), processor, motherboard and even hard drive.

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