When your voltage amounts are unstable (ie: power stays on, but the particular voltage stage differs lots in the 220V common), then I believe that's the sort of scenario in which an AVR is helpful. all lessons and interfaces from the superclass hierarchy (e.g. see Java course is current in https://marioifcys.activablog.com/32942677/5-simple-techniques-for-uninterruptible-power-supply-adalah