AC to DC Power adapter or power converter is a vital area of research nowadays is efficiency enhancement. In this research work we designed two circuit of 45 watt AC to DC power adapter and we used different diode in both circuit. First circuit which we designed which we considerd as real circuit and we used 1N4148 diode in this circuit full bridge rectifier. And simulate this circuit in LTSPICE software. After analysis the result and using the latest Efficiency Enhancement, High-Frequency Operation, Wide Bandgap Semiconductors, Miniaturization and Integration, eliability and Lifetime, Digital Control Techniques, Power Factor Correction, Renewable Energy Integration, Multi-Port Converters, Harmonic Distortion and EMI, Smart Grid and Demand Response, Environmental Impact and Sustainability, Biomedical Applications, and Safety and Standardization factors because These areas of research collectively contribute to the advancement of AC to DC power conversion technology, making it more efficient, reliable, and adaptable to the evolving needs of various industries. We design second circuit which we consider as ideal circuit we used MURS320 diode ideal circuit full bridge rectifier. And we simulate this circuit in LTSPICE software and analysis the simulation result. We get 2.5% efficiency in ideal circuit of 45 watt AC to DC power adapter