Biax

(biaxial ferrite core), a ferrite core with a branched magnetic circuit and two apertures that do not intersect and which have perpendicular axes. It is used as a memory or logic element in technical automation facilities and in digital computer technology.

The memory biax provides for operative recording, storage, and nondestructive readout.

This characteristic is due to the fact that the directions of the magnetic fluxes in the common region of the two closed interconnected magnetic circuits of the biax (the plug wire between the apertures in Figure 1, a, enclosed by the dotted lines) are mutually perpendicular and, upon simultaneous magnetic field reversal (recording of information), the resultant magnetic flux in the plug wire takes up the most favorable orientation (Figure 1, b). Here the magnetic fluxes around each aperture vary up to 0.7 of their maximum value. An interrogation pulse causes a practically instantaneous change of orientation of the domains of the plug wire in the direction of the flux in the interrogation magnetic circuit. This leads to a reduction of the flux in the recording magnetic circuit and the emergence of an electromotive force (readout) in the output winding. After the shutoff of the interrogation pulse in the plug wire, the original distribution of the fluxes is restored without additional input.

Figure 1. The biax: (a) symmetrical type, with recording (J_r), interrogation (J_r), and readout (e<>ut) windings; (b) plug wire with magnetic flux vectors for recording (3), interrogation (2), and the resultant (1); (c) asymmetric type BN-6.

The logic biax differs constructionally from the memory type by the absence of a plug wire. During its operation, the magnetic fluxes and their signs vary in the regions of the magnetic circuit common to both apertures.

There are several varieties of biax that differ in construction (symmetrical and nonsymmetric; Figure 1, c), in properties of magnetic circuit material, and so on. The primary virtues of the biax are its small dimensions, very rapid response (particularly in readout at small energy inputs), high reliability, and comparatively low cost for automated production and sorting.