Harmonics are periodic distortions of voltage, current, or ability sine waves. Harmonics in electricity distribution techniques are often a result of non-linear masses such as switched method dc electrical power provides and adjustable speed motor drives. + Các Internet site, ?ng d?ng l?y d? li?u x? s? tr?c ti?p t? Minh Ng?c: K?t qu? c?p nh?t tr�