Harmonics are periodic distortions of voltage, present, or ability sine waves. Harmonics in electrical power distribution systems are frequently attributable to non-linear hundreds which include switched method dc power materials and adjustable speed motor drives. trong m?t kho?n th?i gian nh?t ??nh tr??c khi ?i?u ch?nh, t?t nh?t b?n nên dùng ph