Harmonics are periodic distortions of voltage, current, or electricity sine waves. Harmonics in electrical power distribution programs tend to be due to non-linear masses for instance switched mode dc electric power materials and adjustable velocity motor drives.?úng v?y, vi?c r?i kèo nh? r?i bom s? khi?n b?n m?t t?p trung và không th? th?ng l?