Harmonics are periodic distortions of voltage, current, or electricity sine waves. Harmonics in electric power distribution units are often a result of non-linear hundreds for instance switched method dc ability provides and adjustable speed motor drives.Th?ng kê t?n su?t loto Th?ng kê t?n su?t c?p loto Th?ng kê Lô gan Th?ng kê two s? cu?i gi?