A new crossed-film cryotron structure with superimposed controls

Crossed-film cryotron circuits could be considerably improved if a structure were available in which one control could aid or oppose the effect of another. It is shown that this can be achieved by superimposing two controls in perfect registry. However, this is a difficult task. An alternative structure which does not have this disadvantage has been found. This structure employs superimposed controls of different widths, the widest one being closest to the gate film and projecting beyond the others. It has been proved theoretically and confirmed experimentally that current in any one control of this structure can effectively cancel the effect of the same current in any other. Several applications of the device are described. They include a negative impedance circuit, a current polarity sensor, and various logic elements. The relationship of the multiple-control cryotron to the single-control cryotron is assessed.