This paper presents the analysis of supply side power factor in a non-sinusoidal environment. For this purpose, single phase bidirectional and unidirectional AC voltage regulators are considered and operate with resistive loads. The phase angle control technique is used to switch on and off the thyristors connected in these converters. The experimental setup was made to measure the supply side power factor and the total harmonic distortion by using power quality analyzer. Finally, a comparison of the power factor on source side and the harmonics in both AC voltage regulators is made. It is concluded from the results that input side power factor of these converters is less than unity even at resistive loads due to generation of harmonics.