Backup power supplies, do provide computer back up power and are rated according to the amount of reserve power they can hold. To be precise, all computer backup power systems receive a V/A rating that is an abbreviation for volts/amps. Almost all computer backup power systems do provide a level of power protection that prevent occasional power surges from causing damage to a computer. Many also do provide a software package which automatically shuts down an unattended computer should a power outage occur.
In most cases, there is no known way of establishing what Volt/Ampere rating one should purchase for his desktop computer without having to employ very sophisticated equipment, like Kill a Watt meter, just to mention one brand that is very popular. If one uses a meter to determine the power usage of a computer it is imperative that he leaves a safety margin between the estimated power required by the machine and the Volt/Ampere rating of the UPS. A reliable rule of thumb is to buy a UPS that has a Volt/Ampere rating almost two times the maximum measured power utilized by the computer.
Part of the difficulty encountered in measuring a desktop computer’s power requirements is the fact that the amount of power it utilizes is subject to the tasks it is undertaking. For example, a computer which is on but its monitor is put off will use less power than he one having its monitor on, especially when the monitor is CRT. Also a computer running a maintenance routine like disk defragmentation will use more power than the one that is running normal programs like the office suite.
Once one has established the maximum load his computer might use, calculating the time a UPS can supply power to the desktop computer is much more straightforward. Ohm’s law does tell us that power, which is measured in watts, is equal to voltage multiplied by the current which is measured in amperes.
Many computer backup power systems include a surge protector for non-battery backup electrical sockets, and for telephone as well as network cabling. This additional protection does help prevent damage to electronics. This is usually found in an office environment. One should take care not to plug a laser printer into a UPS. This is because they can draw far much more power when they warm up than many consumer-grade systems are able to safely provide. One should only plug devices which are absolutely needed in the Computer backup power system outlets.