Final answer:
A UPS, or Uninterruptible Power Supply, is the device used to protect a computer from unexpected power outages by providing temporary power and surge protection.
Step-by-step explanation:
You can protect your computer from unexpected power outages by using a Uninterruptible Power Supply (UPS). A UPS is a device that provides battery backup when the electrical power fails or drops to an unacceptable voltage level. Small UPS units can power a computer for several minutes; enough time to save data and safely shut down the system. Larger units have enough power for several hours, and in addition to providing power during an outage, most UPS also condition the power and provide protection from power surges.