The field of engineering that deals with the design and analysis of power conversion circuits and devices is called power electronics, although power supply design is a true cross-disciplinary task. It involves the circuit, magnetics, thermal management, control and compliance issues. That’s why switch mode PSUs offer greater efficiency compared with linear ones. Such units are also smaller in size and lighter in weight due to the reduced size of passive components and lower heat generation. There are different types of PSU depending on their mode of operation. Here you will find a tutorial, tools, reviews, schematics, and other free online resources on all aspects of switching power supply design and selection, information on other energy conversion devices, as well as basic electrical engineering reference and electronic formulas.