This fourth and last volume is devoted to DC-AC conversion, i.e. to inverters. For the same reasons as for the choppers, such converters have much evolved recently: multiplied uses of the pulse width modulation. A bookreviewing the last progress in the field was therefore particularly needed. Contents: Introduction. - Presentation of the study. - Constant-voltage source inverters with square or quasi-square wave output. - Constant-voltage inverters with pulse width modulation. - Commutations in constant-voltage source inverters. - Constant-current sourceinverters. - Resonant-load inverters.