Now-a-days the usage of power electronic systems has expanded to new and wide application range but the presence of harmonics could even be an enormous problem. The nonlinear operation of power semi converters and presence of bridge rectifiers in electronic devices for AC-DC conversion resulted during a high Total Harmonic Distortion (THD) and low Power Factor (PF). Thus, there arise the need for an influence factor correction circuit in conjunction with the power converters for limiting the allowable harmonics on the power lines, and hence to reinforce the power factor. Active PFC and Passive PFC are the two power factor correction techniques. This paper aims to develop a lively power factor correction (PFC) for single phase AC/DC converter, alongside a Two Switch Buck- Boost converter. The converter is designed and simulated in MATLAB Simulink Results obtained from simulation shows Power factor is improved at source side.