Metal rectifiers

The paper deals in detail only with the two types of metal rectifier which have found general application in industry, namely the copper-oxide and selenium rectifiers. The history of these is given briefly, with particular reference to the main developments which have brought them to their present state of efficiency. This section leads up to modern methods of manufacture. The fundamental direct-current electrical characteristics, upon which the performance depends, and the manner in which they are influenced by various factors, are described. The simple basic theory which governs all types of rectifier is discussed with reference to metal rectifiers in relation to their chemical and physical forms. Finally, the method by which the correct working conditions are deduced from the characteristics is described.