This book deals with analysis and simulation of ZVT based Boost PFC Converter with EMI Filter in PSpice software of version 9.2.The Boost converter of Power Factor Correction (PFC) Circuit is analyzed, designed and then simulated for resistive load. It gives better power factor at the input side and constant voltage and current at the output side. The drawback is the current has more noise i.e. EMI.The power factor is further improved using ZVS technique. In the converter circuit, the active clamping branch composed of a clamping capacitor and an active switch is placed in parallel with resonant inductor. Also, the main switch, the auxiliary switch, the clamping capacitor, the boost diode and the output capacitor form a voltage loop. The power factor is further improved using ZVT technique.The ZVT technique allows the increase in switching frequency without increase in switching losses .ZVT converter operates at a fixed frequency while achieving zero voltage turn on of the main switch and zero current turn off of the boost diode.In this book,it is proposed that ZVT based Boost PFC Converter with EMI Filter is a better solution for power factor improvement in AC to DC Converters.