Nonlinear resistors in logical switching circuits

Nonlinear resistors may be used to replace whole arrays of crystal rectifiers in certain logical switching circuits. Where such replacement is possible, considerable savings in fabrication and component costs may be effected, because both the nonlinear resistors and the associated connecting busses are fabricated by applying printed circuit techniques to standard plastic- or ceramic-bonded sheets of semiconductors such as granular silicon carbide. The manner in which groups of nonlinear resistors may be used in logical switching circuits is described here in terms of simple circuits which employ both "matrix logic" and "grid logic." The technique is experimentally illustrated with the aid of a pair of simple matrix-type function switches, encoded as binary-to-octal converters. The first employs individual nonlinear resistors as the switching elements; the second is fabricated from a rubber-bonded sheet of granular silicon carbide. Two similarly-constructed decoding matrices are used to transform the converters into three-binary-digit adders. The output voltage-patterns for these devices are compared photographically.