A directly-coupled serial adder designed for use in a digital differential analyser

A brief introduction to the technique of directly-coupled logical circuits is given together with basic logical circuit diagrams. It is proposed that for maximum economy and optimum operational reliability, a single type of transistor and a single value of resistor should be used throughout the equipment and that design reliability should be based on the probability of worst-case parameters not being exceeded. Practical designs based on the above theories are shown and limited reliability figures quoted.