Harmonics are periodic distortions of voltage, current, or ability sine waves. Harmonics in electricity distribution units will often be caused by non-linear hundreds such as switched mode dc electricity 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?Nhi?u trang th? thao t