The design and use of logical devices using saturable magnetic cores

The minimum requirements for an elementary `building brick¿ for a serial digital computer are considered. It is found that each unit must provide power gain and must have an input/output characteristic such that the amplitude standardization of both `0¿s and `1¿s is ensured. Each unit must also provide a time restandardization action, and this inevitably requires a finite time delay. Lastly, it is found that a simple analogue addition and discrimination at the inputs provides all the usual simple logical operations and enables complicated systems to be constructed economically. A technique for designing such building bricks, using magnetic cores operating at a digit frequency of about 100 kc/s to obtain both the input discrimination and the power gain, is described. Examples are given of the way in which these units can be assembled to provide various commonly required computer functions, and the likely limitations in their use are outlined.