Power disturbances are surprisingly common, though most go unnoticed as they are unpredictable and do not show any signs of happening until it is too late. While extreme power spikes like lightning strikes can literally sear electronics, less noticeable power surges can incrementally degrade circuitry over a period of time. PC surge protectors or laptop surge protectors are commonly used to avoid these types of damage, but these types of computer surge protectors do not protect systems from data erasure, system crashes, and performance problems associated with blackouts and brownouts. For those types of damage a UPS surge protector (also know as a battery backup surge protector) is required.
UPS stands for Uninterrupted Power Supply and is a system that uses a battery to supply power to electronic components for long enough to allow them to be powered down. There are three main types of UPS systems, Standby systems, Line-interactive systems, and online systems. Each offers an increasingly higher level of protection, and a higher cost to go along with it.
Standby UPS Systems are designed to detect total power loss and respond by supplying AC power for a given period of time (depending on battery rating). They provide battery backup, plus surge protection, but do not protect against brownouts or other low power situations.
Line-interactive UPS systems use Automatic Voltage Regulation (AVR) to compensate for power fluctuations by boosting or trimming power when required to ensure well regulated power to connected devices. Unlike Standby UPS systems, the AVR feature of Line-interactive systems can compensate for situations in which power is too low but not low enough to trigger a full battery backup.
While Line-interactive systems more effectively regulate power, minor power fluctuations can still make it through to components as it takes the AVR circuitry time to react to sudden power fluctuations. Online UPS systems offer the highest degree of protection. By converting incoming AC current to DC and then inverting it back into AC power, Online systems produce clean, well isolated current that is largely free of even slight power fluctuations. However, these systems require more sophisticated electronics and tend to cost more than the other two systems.