Textbook in PDF format This book entails every reader to repeat (and verify) every single study provided by author by delivering all necessary data for the circuit to be simulated by the user on a platform which is free. This is a student-oriented textbook covering the subject of producing a DC power supply voltage (current and power) for electronic circuits and systems. The motivation for this book comes from the fact that practically all contemporary books on the power supply are power oriented. The community is obsessed by the renewables and energy delivering systems so that powering electronics is almost forgotten. The book presents facts that the design requirements for a converter differ if one looks for power supply for electronics, from the ones intended to be used in power delivering systems to large consumers. So, in this book, "all" existing solutions are re-considered from the point of view of applicability to electronics. Along the development of proper design procedures (and formulas) exhaustive analysis is performed looking to them from as many as possible aspects. It brings the reader much closer to the circuit than the "hand drawn" time domain responses distributed in the existing textbooks. A set of solved problems is added to further increase the acceptance of the knowledge delivered