Switching transistors

Abstract

Transistors are being used more and more frequently as components of computing systems. This increasing popularity can be attributed to their small size, high efficiency, and potential reliability. The size and efficiency of transistors are sufficiently well known to require no further discussion here. On the reliability question, it is pertinent to note that transistors have been in operation in some telephone applications for several years with failure rates of about 0.05% per thousand hours. This figure compares favorably with that for the best vacuum tubes and there is every confidence that newer devices will exhibit much higher reliability. The first part of this paper is devoted to a discussion of the electrical characteristics that make conventional transistors (n-p-n and p-n-p) attractive in computing applications. The second part deals with a family of 4-region (p-n-p-n) devices which are now under development and in some cases in early production. These devices exhibit a bistable characteristic and their use may lead to a considerable simplification of computer circuitry.