The paper describes the types of high-voltage steel-tank rectifier used in the higher-power radio stations constructed by the British Broadcasting Corporation, including a recent type of pumpless air-cooled equipment, and gives a review of their performance in service.Appendices contain some analytical and design data for the various types of rectifier connection used in practice, smoothing circuits, and grid-control features, with particular reference to stations in which rectifiers form the bulk of the load, and in which, owing to Class B modulation, the load on the rectifier fluctuates over wide limits at syllabic frequency.