A UPS is a backup battery power supply for your desktop computer and any other peripherals you do not want to lose power in a electrical outage. A UPS doesn’t just protect your equipment against power loss, it can also ensure that your equipment will keep running if there are spikes or surges in power.
A Standby UPS is the most widely used in homes and small businesses. They’re small and inexpensive. When the UPS detects a power failure, it kicks in and switches over to battery power (hence, UPS – Uninterruptible Power Supply). The battery in a standby UPS only holds enough power to run your equipment for a few minutes – just enough time to save your files and power down properly.
Not only will a UPS help prevent data loss during power outages, but it can also help maintain the life of your PC’s internal parts. Sudden drops in power can damage internal circuitry. Especially if it is an instantaneous brown-out where the power immediately comes back. UPS’s also double as surge protectors.
Most standby UPS’s have 2 sets of outlets. One set for battery + surge protection, and the other set for surge only protection. Only plug the absolute necessities such as PC, monitor and external hard drives into the battery backup set, so that if an outage does occur, you have enough time to close your programs and shut down properly (and most newer models will connect to your PC via USB for you to configure unattended automated shut downs).
Peripherals such as printers, speakers and battery containing devices such as laptops, tablets & phones only need surge protection.
Also, never plug laser printers into the battery protected outlets. They will not work properly due to their power requirements, and you may risk damaging the UPS and printers circuitry.
Most UPS’s advertise an estimated amount of battery running time. In real life use, you can estimate about 1/3rd of the advertised time.
Also, if you have unstable voltage levels, look for a UPS with a voltage regulator (AVR). These will maintain healthy voltage levels for your battery protected equipment.
You may also want to think about getting a dedicated UPS for your internet modem and router to reduce wear and tear, and keep you online in case of brownouts. These two types of equipment use very little power compared to a PC, so you needn’t get a very powerful one for them.