This comparison shows the degree of improvement that is possible using active power factor correction converters. The rectifier with capacitive filter circuit on the left shows narrow conduction intervals with high harmonic content, a power factor of 0.55, and a Total Harmonic Distortion rating of 137%, due to all the energy transfer occurring in high order harmonics. It should be noted that with a real world AC source impedance, the AC waveform itself is distorted by this load condition. When an AC branch sees many loads like this on the line, it can result in substantial trapezoidal distortion of the line voltage waveform. The waveform on the right shows the results of implementing an active power factor correction circuit, which can reduce line current harmonic distortion to a few percent or less, and raise the Power Factor to near unity. Distortion of the AC voltage waveform is now gone.