Harmonics are periodic distortions of voltage, recent, or ability sine waves. Harmonics in electricity distribution devices in many cases are due to non-linear loads which include switched mode dc electrical power provides and adjustable speed motor drives. Gi?i m?i (bao g?m t?t c? gi?i nào có s? thay ??i, c?p nh?t m?i ho?c ?i?u ch?nh).) b?n l?u