Harmonics are periodic distortions of voltage, present, or electric power sine waves. Harmonics in power distribution methods are sometimes a result of non-linear masses for instance switched manner dc electric power provides and adjustable speed motor drives.??i v?i nh?ng ng??i ch?i có nhi?u kinh trong l?nh v?c cá c??c thì vi?c nh?n ??nh keonha