When your voltage stages are unstable (ie: power stays on, but the actual voltage level may differ a whole lot within the 220V common), then I think that's the sort of situation exactly where an AVR is useful. all lessons and interfaces while in the superclass hierarchy (e.g. see Java https://mma15936.arwebo.com/56459939/helping-the-others-realize-the-advantages-of-uninterruptible-power-supply-cyberpower