A Generalized Resistor-Transistor Logic Circuit and Some Applications

This paper discusses a generalized resistor-transistor logic circuit; i.e., the output produces a signal when any m out of the n inputs are ``on.´´ Practical limitations such as using precision power supplies and components are discussed. However, for smaller values of n and m, circuits could be designed such that no special precision components and supplies would be required. Several practical circuits are worked out, including a two-transistor binary full adder, a three-transistor comparator and a one-transistor-per-bit-ring counter. These circuits, especially the first two, are uniquely simple and low in cost. They can be incorporated with other circuits to simplify a digital system. It is felt that with ordinary supplies (less than 5 per cent voltage variation) and 1 to 5 per cent resistors, these circuits can be designed to be very reliable as one would expect from conventional circuits. The slight increase in cost of power supplies and components, if any, is, in many cases, over compensated by the simplicity of these circuits. Experimental circuits employing germanium alloy junction transistors operate successfully at pulse rate up to 500 kc and an ambient temerature of 50°C.