What device is used to protect a computer from problems caused by power changes?

The device specifically used to protect a computer from issues related to power changes is the Uninterruptible Power Supply (UPS). A UPS provides backup power during electrical outages and regulates voltage levels, which helps prevent damage from sudden surges, dips, or total loss of power. It can give users enough time to save work and shut down systems safely, thus protecting sensitive components from abrupt power loss or surges that can lead to data loss or hardware failure.

While a surge protector offers some level of protection against spikes in voltage, it does not provide backup power during outages. The Power Supply Unit (PSU) converts electrical power from an outlet into usable power for the computer's internal components but does not specifically regulate or protect against power changes. A voltage regulator stabilizes output voltage to ensure that the connected devices receive consistent voltage levels, but again, it does not offer backup power in the event of an outage. Therefore, the Uninterruptible Power Supply is the most comprehensive solution for protecting computers from problems caused by power fluctuations.