Transistors in Switching Circuits

The general transistor properties of small size and weight, low power and voltage, and potential long life suggest extensive application of transistors to pulse- or switching-type systems of computer or computer-like nature. It is possible to devise simple regenerative circuits which perform the normally employed functions of waveform generation, level restoration, delay, storage (registry or memory), and counting. The discussion is limited to point-contact type transistors in which the alpha or current gain is in excess of unity and to a particular feedback configuration. Such circuits, which are of the so-called trigger type, are postulated to involve negative resistance. On this basis an analysis, which approximates the negative-resistance characteristic by three intersecting broken lines, is developed. Conclusions which are useful to circuit and device design are reached. The analysis is deemed sufficiently accurate for first-order equilibrium calculations. Transistors having properties specifically intended for pulse service in the circuits described have been developed. Their properties, limitations, and parameter characterizations are discussed at some length.