The stopper circuit: A controllable threshold circuit for all-magnetic logic

A group of all-magnetic logic circuits, which have been realized by interconnecting simple toroids, is described. These circuits employ what may be described as dynamic threshold control to select signal paths. Application of this technique results in a significant increase in power gain, which is directly translated into increased operating range. The scheme, classified as a 4-phase nonresistance scheme, is capable of operating at speeds in excess of 100 kHz. The use of toroids rather than mulipath structures has resulted in increased flexibility in design, since the toroids can be selected specifically to match the requirements of each portion of the circuit. Minor loop characteristics of the cores are described in which an enhancement effect has been observed in certain materials. This enhancement is used to compensate for the softening of the threshold that typically occurs in partially set cores. Low-impedance coupling between the several cores that comprise each circuit (as well as between circuits) is emphasized. These circuits are capable of performing the basic logic functions required for general logic and also are capable of nondestructive readout. Operating data on experimental circuits connected to form a 14-stage ring counter is included.