Transistor Circuits for Analog and Digital Systems

Transistors, because of their reliability, small power consumption, unci small si/x; find a natural field of application in electronic computers and data transmission systems. These advantages have already been realized by using point contact transistors in high speed digital computers.' This paper describes the application of junction transistors to precision circuits which arc used in dc analog computers and in the input and output circuits of digital systems. The three basic circuits which arc used in these applications are a summing amplifier, an integrator, and a voltage comparator. A general procedure for designing these t ransistor circuits is given with particular emphasis placed on new design methods that are necessitated by the properties of junction transistors. The design principles are illustrated by specific circuits. The fundamental considerations in the design of transistor operational amplifiers are discussed in Section 2.0. In Section 3.0 an illustrative summing amplifier is described, which has a dc accuracy of better than one part in 5,000 throughout ail operating temperature range of 0 to 50°C. The feedback in this amplifier is maintained over a broad enough frequency band so that full accuracy is attained in about 100 microseconds. The design of a specific transistor integrator is presented in Section · S u b m i t t e d in partial fulfillment of the requirements for the degree of D o c t o r of Electrical Engineering at the Polytechnic I n s t i t u t e of B r o o k l y n .