Harmonics are periodic distortions of voltage, recent, or ability sine waves. Harmonics in power distribution devices will often be because of non-linear hundreds such as switched method dc energy supplies and adjustable velocity motor drives.V?i nhi?u n?m kinh nghi?m trong l?nh v?c nhan dinh bong da, Bongdavua Television mang ??n cho các tay ch?i