Personal computer has significantly contributed to harmonics problem by lowering voltage
distribution system. The current THD for personal computer exceed 100%, as the result of high level individual distortions introduced by the third and fifth harmonics. The total current drawn by personal computer and its monitor is less than 2 A, but a typical high-rise building can contain several hundred computers and monitors. The net effect of this on the total current harmonic distortion of a facility is not difficult to visualize.