CompTIA Network+ Practice Test

Which type of UPS activates when the power goes out?

1. Line-interactive UPS

2. On-line/Double-conversion UPS

3. Offline/Standby UPS

4. Backup only UPS

The correct answer is: Offline/Standby UPS

The offline or standby UPS is designed to activate and supply power to connected devices almost immediately when it detects a power outage. In normal operating conditions, it allows utility power to flow directly to the connected equipment, effectively functioning as a pass-through. When a power failure is detected, the UPS switches to battery power, usually in a matter of milliseconds, ensuring that there is minimal disruption to the devices. This type of UPS is particularly popular for home and small business use, where cost-effectiveness is essential, and the devices being powered do not require the continuous regulation of output voltage. It provides enough time for critical equipment to either continue functioning briefly or shut down properly without data loss or damage. The other types of UPS serve different operational purposes. For instance, a line-interactive UPS incorporates an automatic voltage regulator, allowing it to handle minor fluctuations and sometimes allowing for partial power to be maintained even during brownouts, which is different from the immediate activation upon outage in an offline UPS. An online or double-conversion UPS continuously converts incoming AC power to DC and then back to AC, providing a constant and clean power supply, thus operating with battery power at all times. Backup only UPS might suggest a non-functional descriptor, as it doesn't align with a recognized category