Which statement is true about power supplies for IT equipment?

The statement that power supplies for IT equipment remain unaffected by frequency variations is accurate because many modern power supply designs incorporate methods to mitigate the impact of frequency fluctuations. It is important for IT equipment to maintain consistent performance, and power supplies often include features such as voltage regulation and filtering that help to stabilize the output despite changes in input frequency.

In scenarios where frequency variations do occur, the power supply may still continue to operate within certain parameters without a significant negative impact on the equipment it serves. This reliability is critical in IT environments where continuous operation is essential.

The other statements, while they touch on aspects of power supplies, do not fully capture the resilience most modern power supplies have against frequency changes. For instance, power supplies are designed to function across a range of voltages and frequencies, hence the idea that they require constant voltage to function does not account for their adaptability. Additionally, while harmonics can cause issues, the primary concern with harmonics relates more to efficiency and performance degradation rather than outright failure.