Lets talk about UPS power supplies

[Netscan]

thanks! do you know how I would check to see if my power supply is pfc? I have a Dell Optiplex 7040 SFF i5-650 but who knows maybe it was switched out at some point as i bought it used. Is there something i can type into the cmd to find? or do i need to open the pc and look for something written on the PSU?

In my anecdotal experience, I've only had 1 brand of PFC PSUs fail to stay up during switch-over to battery with a stepped sine wave UPS, the Antec Earthwatts series -- 3 out of 3 failed to stay online. Most decent power supplies are specced with the proper hold-up time. Extended use on battery can harm the electronics, tho.

If up-time is what you're after, then a proper sine wave is what you want to protect sensitive electronics -- but a cheap, consumer UPS is not meant to provide power long term, it's only to give enough time for the system to shut down gracefully. Sizing the UPS correctly is more important: Computers containing PFC (Power Factor Corrected) power supplies and their use Back-UPS and Smart-UPS SC with Step Approximated Sine waves.