Abstract: A method for minimizing the inhomogeneity of a static magnetic field, produced by a main magnet, over a selected arbitrary volume, by operation of a plurality N of shimming coils each independently producing an associated shimming magnetic field having an associated inhomogeneity which is a function of spatial location over that same volume, uses the steps of: measuring the magnitude of the main magnet field, in the absence of all shimming fields, at a plurality of locations X.sub.i upon the surface of an imaginary sphere enclosing the arbitrary volume; measuring the polarity and magnitude of each of the N shimming fields, with respect to the polarity and magnitude of a D.C. current flowing through the associated shimming coil, at the same plurality of locations X.sub.i upon the imaginary sphere surface; determining the weighted mean-square variation of the total field at each of another plurality of points Y.sub.

Abstract: A conductive multilevel liquid sensor uses conventional integrated circuits such as inverters and voltage comparators as signal detectors, and a flat cable having corrosion-resistant probe conductors of different lengths as the sensing probe assembly. The binary encoded outputs of the signal detectors identify the sensed liquid level. A continuous level control is realized by the addition of timing logic, and sensor operation range is improved by having the voltage at one comparator input be adaptive to the change in liquid conductivity.

Abstract: An easily assembled transverse magnetic printing head and method for making same are disclosed for use in a coincident current, matrix-driven, transverse printing head. In accordance with one embodiment of the present invention, digit lines pass through a recording gap in mirror image fashion as between adjacent word groupings. Similarly, the word line patterns are arranged on a printed circuit board in a zig-zag fashion. A feature common to both the word and digit line printed circuits, however, is the presence of a small expanse of circuit wiring unsupported by printed circuit substrate material through which a high permeability magnetic comb structure is inserted to form required recording gaps. The coincident current scheme is retained by driving the digit lines from alternating directions. The arrangement of the digit lines in the present invention permits the use of a planar printed circuit with no crossovers and therefore a circuit which is easily fabricated in a flexible, printed circuit design.

Abstract: In order to achieve higher resolution in printed data, separate magnetic printing head sub-assemblies are adjacently disposed with respect to each other. Each sub-assembly includes a high permeability magnetic comb structure with teeth protruding through elongated slots in a pair of flexible printed circuit boards. High resolution is achieved by a relative offset of the comb teeth so that the teeth of the comb in the second sub-assembly align with the gaps in between the comb teeth in the first sub-assembly.

Abstract: The signal-to-noise ratio as measured by the ratio of the full select magnetic field levels to the half select magnetic field levels, is improved in a coincident current magnetic printing head by providing means for producing a bias magnetic field which is at least somewhat opposed to the signal magnetic fields.