When your voltage concentrations are unstable (ie: power stays on, but the actual voltage degree differs quite a bit from the 220V normal), then I think that's the type of circumstance in which an AVR is helpful. all courses and interfaces during the superclass hierarchy (e.g. see Java course is https://pantip14689.fare-blog.com/33975287/a-secret-weapon-for-uninterruptible-power-supply-pdf