A number of papers on transistor convertors have been published, but they have been mainly concerned with types using a single transistor, although, for some years, transistor convertors have been used in push-pull systems. The paper analyses waveforms in push-pull transistor convertors and presents a simple method of design.Transistor push-pull convertors, unlike those using a single transistor, do not need cores which can store magnetic energy. Thus materials with rectangular hysteresis loops as well as those with constant permeability can be used.