Current-operated diode logic gates

The realization of switching functions using current-operated diode logic gates, which employ the direction of current as the binary variable, is presented. Two realization methods are discussed. The dual method consists of a set of rules which are analogous to the procedures employed for the realization of voltage-operated circuits. The lattice method is based on the transmission characteristics of a lattice network of four series-connected diodes. Either method is capable of realizing any arbitrary transmission function, although the number of diodes required may be different. Hybrid networks, which combine the advantages of both methods, are described to illustrate the versatility of current-operated techniques. Practical design procedures are included to guide the designer in the application of the realization rules. A static multiplier, capable of simultaneously multiplying two 4-bit binary numbers, was designed and built to demonstrate the practicability of current-operated diode logic gates. Approximately 270 diodes were required to construct the twenty gates used in the static multiplier. Dynamic tests of the assembled system indicated a reliable capability of 333,000 multiplications per second.