Abstract :
The paper describes a number of binary counting circuits having junction transistors and square-hysteresis-loop magnetic cores as the basic circuit elements. The cores have two well-defined remanent magnetic states which provide the necessary information storage when the circuit is quiescent, and the transistors are used as pulse-shaping amplifiers which provide output signals and `switch¿ the cores from one remanent state to the other. Cores of ferrite material made for matrix storage systems are used; they have a change-over time of less than a microsecond and, in conjunction with junction transistors at present available, limit the highest counting rate to 2 × 105 pulses/sec. In the circuits described, the emitter and base contacts of the transistor are connected across a winding on the core. The emitter is earthed, and the collector, via the load, is connected to a source of negative voltage. Other windings are available on the core, and flux change in a specified direction causes the transistor to be turned on. When the flux change is complete, the collector current ceases after a short delay. The pulse duration may be controlled by a bias voltage applied between the emitter and the base. Most of the counting circuits include a regenerative loop back to the core in series with the collector load. Core-transistor circuits consume little mean power and this, coupled with compactness, simplicity and reliability, seems to make the combination very suitable for digital-computer applications.
