This paper represents a comparative study among different types of existing single phase AC to DC step down converter. Their performances and outputs have been analyzed depending on their equations. Different parameters such as voltage gain, harmonic contents in input current, parameters of changing output voltage are compared among three different existing single phase AC to DC converters. This research also highlights the advantages and drawbacks of these converters. Simulations of the converters are performed using MATLAB/SIMULINK and PSIM.