Some power electronic converters are specifically designed to power equipment under a smoothed DC voltage. Therefore, the filtering part necessarily involves the use of auxiliary passive components (inductors and capacitors). This book deals with technical aspects such as classical separation between isolated and non-isolated power supplies, and soft switching through a special converter. It addresses the problem of regulating the output voltage of the switching power supplies in terms of modeling and obtaining transfer of SMPS functions.Power Electronics for Industry and Transport, Volume 3, offers a case study of an isolated flyback power which the complete design is presented: the active and passive components are sized based on the specifications initially set. Particular attention is given to the converter output capacitors and all the surrounding organs.