A generalized concept of 'sources' that embraces both power generators and power consumers is presented. This approach simplifies the basic topological aspects of power electronic converter circuits, which are reduced to an array of switches for selectively interconnecting two source systems. Capacitive and inductive filters can modify the nature of the systems, because they act as short-time sources and determine whether the converter sees a voltage source or a current source at its terminals. These differing source qualities require different types of switching devices and have ramifications in the mode of operation of the equipment. Some basic configurations are presented, and their significant properties are described, with emphasis on the most widely used circuits in high-power equipment, particularly AC/DC converters. >