Firstly, a PSU is a device that converts inputted direct current (DC) or alternating current (AC) into DC power outputs. Ultimately, its purpose is to provide energy for a data storage appliance or a server. A single output PSU delivers most of its power to one DC output. A multi-output PSU supplies it to more than one.
2019/424 specifies a minimum efficiency that a PSU must have at a certain percentage of its rated load level. For example, from January 1st, 2023, a PSU at 20% of its rated load must be at least:
- 90% efficient for a multi-output;
- 94% efficient for a single output.