What is a characteristic of online uninterruptible power supply (UPS) systems?

Online uninterruptible power supply (UPS) systems are specifically designed to provide continuous power to connected loads, ensuring that electronic equipment receives clean and stable electricity. A primary characteristic of these systems is that they are always active, converting incoming AC power to DC power and then back to AC. This process allows for a constant supply of power without interruptions, effectively protecting against power disturbances.

These systems are particularly recommended for data centers and telecommunications because they provide the highest level of power protection, including the ability to filter out line noise and voltage fluctuations. In environments where equipment reliability is crucial, the use of online UPS systems helps maintain operational continuity and protect sensitive devices from downtime or damage caused by power issues.

In contrast, some of the other options do not accurately describe the nature of online UPS systems. For instance, their operation is not limited to just power outages, nor are they exclusively used in residential settings. Additionally, online UPS systems do indeed offer surge protection, helping to safeguard equipment from voltage spikes.