If you're using a computer and there is a power outage, physical damage can occur as well as losing your data. Many users have surge protectors that guard against a sudden increase of electricity (above the standard 120 volts) that could possibly harm components, but they do not prevent data loss. Moreover, depending on how strong the surge, even a regular surge protector may not protect from extensive physical damage.An uninterruptible power supply (UPS) is an external box containing a battery that provides power to a computer and other electronics in case there is a loss of power. There are two types: standby (offline) and online.
A standby UPS uses regular AC power from a wall outlet for a computer. When a problem arises, it immediately switches (usually under 5 milliseconds) to the battery using an inverter so the PC will not lose power and can be shut down properly. The battery charges as long as the unit connects to AC power. With an online UPS, the computer is constantly using the battery, which is continuously recharged. As a result, there is no switch over time as with a standby. The DC power produced by the charger is converted to AC by the inverter. This is an on-going cycle. During a power failure, the battery sends power to the inverter. These types are also called a true UPS.
A standby UPS is much cheaper than an online and is mostly used for homes and small offices.
