Selenium rectifiers in 1965

The review gives a detailed picture of the state of knowledge on the conductivity mechanism in selenium before describing the advances in rectifiers made in the last 10 to 15 years. These consist mainly of a reduction in the voltage drop across the rectifier in the forward direction and the virtual elimination of the ageing phenomenon under certain conditions. Both these steps permit the power rating to be increased so that for a given size of rectifier the rating has trebled over the last ten years.