Harmonics are periodic distortions of voltage, present-day, or electricity sine waves. Harmonics in power distribution devices tend to be attributable to non-linear loads including switched mode dc electrical power provides and adjustable speed motor drives.Th?ng kê t? ??ng c?p nh?t khi k?t thúc bu?i t??ng thu?t tr?c ti?p k?t qu? x? s?T? ch?c ch?