A decade ring counter using avalanche-operated junction transistors

Summary form only given, as follows. The avalanche mode of operation for junction transistors is encountered at higher-than-normal collector voltages. In this avalanche region of operation the electrical character of the junctiontransistor is profoundly altered because of a voltage sensitive current-multiplication occurring at the collector junction. Current controlled N-type negative resistance characteristics suitable for bistable operation are obtained. Important features of these characteristics can be treated analytically to obtain results suitable for design purposes. Important properties associated with the avalanche mode of operation are summarized. The collector characteristics and the emitter input characteristic obtained with avalanche operation are compared and discussed. An equivalent circuit, descriptive of the effect of the avalanche current multiplication, is presented together with basic relationships useful for circuit design. Twelve experimental avalanche-operated junction transistors have been used in a decade ring counter and driver. This represents a saving of two to one in semicoliductor devices, as contrasted to the use of conventionally operated junction transistors for the same function. A like saving of other components is obtained. The ring counter uses a new method of count transfer which provides improved reliability and higher counting speed capability. The driver and counter achieve operation to 500 kc using transistors having a frequency of β cut-off in the range 30 to 40 kc for conventional operation. The counter operates to 300 kc cover atemperature range from below -50°C to +5O°C without compensation or optimized design.