Abstract: A magnetic pole and coil assembly for concentrating eddy currents in a limited peripheral portion of a metal product being examined by the assembly. The assembly comprises at least one winding adapted to produce a magnetic field when supplied with alternating electrical current, and laminations of high permeability magnetic material disposed closely adjacent a portion of the winding to concentrate the magnetic field in the vicinity of the magnetic laminations.

Abstract: A method of both testing all loops of a long serial magnetic bubble domain chip, and repairing the chip for automatic bypass of defective loops. Each repair station associated with each loop is sequentially loaded with a bubble domain. Then new domains are sequentially generated and positioned adjacent each loop. The domains initially loaded into the repair stations are shifted out in parallel for propagation along the loops. The new domains are then loaded in parallel into the repair stations. The domains propagated along the loops are read to determine defective loops, and form a basis for generating a repair pattern. The repair pattern is then loaded in parallel into the repair stations for sealing off defective loops.

Abstract: A device for indicating the direction of rotation of a rotating body forming part of or associated with rotating electrical machine comprises the combination of a probe unit positioned to interrupt magnetic lines of force generated by the electrical machine, a detector for interpreting signals from the probe unit, and an indicator, which can be a center zero current meter or an oscilloscope, for displaying direction of rotation.

Abstract: The electrical conductivity of a lamella of conducting material (e.g., semiconductor wafers or metal films) is measured by introducing the lamella into the oscillatory magnetic field of the inductive element of the L-C tank circuit. The tank circuit is the frequency determining portion of an oscillator which is adjusted, upon sample introduction, to restore the magnitude of oscillation. With suitable choice of circuit parameters, the incremental current in the tank circuit is linearly proportional to the sheet conductivity of the lamella. An exemplary apparatus, operating at approximately 10 MHz with a 1 cm.sup.2 measurement area exhibited approximately 1% linearity over a 100 to 1 range of conductivity with a resolution of approximately one part in 10.sup.4 with a limiting sensitivity of 10.sup.11 carriers per square cm.

Abstract: A color pick-up tube face plate with shading films is disclosed. These shading films are stripe-shaded opaque films, and are formed between the transparent glass plate and the stripe-shaped color filters. As the boundary portions of all the filters are positioned on these shading films, the light incidented around the boundary portions is hindered by the shading films. For this reason, light reflection or scattering around the boundary portions is effectively eliminated, and a pure high quality color picture is obtained.

Abstract: A metal proximity sensor comprised of a housing having a sensing surface and a mounting surface opposite the sensing surface. The sensor is further comprised of a coil positioned within a cavity of a ferromagnetic pot core, wherein both components are positioned within the housing and adjacent the sensing surface. A ferromagnetic shield is provided for shielding the magnetic field, generated by the coil, from electromagnetic energy generated externally of the mounting surface of the housing. A second shield is comprised of a metal layer having a resistivity of less than 3.mu. ohm-centimeters for preventing the electromagnetic field, generated by the coil, from penetrating out of the sensor and through the mounting surface. The second shield is disposed between the first shield and the core. Finally, circuit means is provided for actuating an external load when a metal being detected passes near the sensing surface and through the magnetic field generated by the coil.

Abstract: An improved measurement system for determining the degree of out of synchronism or phase difference of a moving body carrying a row of magnets with respect to a reference signal. A pair of precisely spaced magnetoresistance elements are provided each having a plurality of stripes formed of a ferromagnetic material with an anisotropic characteristic. Each element has an AC power source connected across it, the two power sources being 90.degree. out of phase. Positioned near the magnetoresistance elements is the row of magnets comprised of a plurality of magnet pairs having South pole ends abutting and forming a specific wavelength. As the row of magnets moves relative to the magnetoresistive elements, a changing magnetic flux causes resistance changes in the elements which in turn produces a modulation of the AC power sources which is sensed at the middles of the magnetoresistance elements.

Abstract: A device for controlling the termination of light emission by a flash including means for detecting the light reflected from the subject being illuminated by the flash, integrating means connected to the detecting means for providing a flash termination signal when the total amount of light received by the detecting means reaches a predetermined value, and flash termination means connected to the integrating device and to the flash device for terminating the delivery of electrical energy to the flash device when the signal from the integrating device reaches its predetermined value. The flash termination device is preferably constituted by a novel gas-filled, arc-producing element having identical, unpolarized electrodes and an internal or external triggering electrode.

Abstract: Method and apparatus for determining and applying a feedback current to the two sense windings of a vehicle mounted flux gate compass in order to provide a compensating magnetic field to cancel out the effect of local magnetic disturbance field(s) produced by the vehicle. Two zero crossing detectors for each channel respectively associated with the two sense windings indicate when the output from a sense winding passes through a null. This indication is used to enable a sample and hold circuit for the voltage on the opposite coil. During the calibration sequence the vehicle traverses a complete circular path wherein each coil passes through two nulls resulting in two voltages being sampled and held for each coil. The two pairs of voltages are then averaged, which then results in two resultant voltages which are representative of the lateral and longitudinal components with respect to the vehicle of the disturbance field.

Abstract: An indicator for flow of fault current in a conductor is enclosed in a housing carrying a metallic clamp for detachable mounting on the conductor. The indicator is operated by closure of a switch in response to flow of fault current in the conductor and is reset by the voltage developed between the clamp and ground. The indicator is checked by application of a permanent magnet to close the switch and an external voltage to reset the indicator. The indicator also can be reset by flow of normal current in the conductor employing a winding on a magnetic core surrounding the conductor and encapsulated with the switch.

Abstract: An eddy current coil test assembly comprises a printed circuit board having respective conductors which form the excitation coil winding, the sensing coil winding, the input transformer winding, the output transformer winding and the connections between these respective elements. Pot core type transformers are mounted in close proximity to said windings. The printed transformer windings constitute respectively the secondary winding of the input transformer and the primary winding of the output transformer.

Abstract: A device for testing magnetic thin layers for defects, in particular "bubble" films in which a magnetic medium in which a recurring pattern of elongate areas magnetized alternately in opposite senses is recorded is moved relative to the layer while the layer is opposite the magnetic medium so that a corresponding pattern of mutually parallel strip-shaped "bubble" domains is formed in the film. Deviations in said pattern are an indication of defects in the film.

Abstract: A probe for electromagnetic measurement of the thickness of a layer of material applied to a base of dissimilar material consists of an elongated ferro-magnetic core surrounded by an electrical coil several diameters larger than the diameter of the core and having one end placed close to the plane of the pole face of the core so that measurements involving magnetic materials can be undertaken by utilizing variations in magnetic flux path at low energization frequencies while measurements involving electrically conductive materials are undertaken by utilizing eddy currents induced at high energization frequencies.

Abstract: The invention concerns a device for the non-destructive measurement of the remanent flux density of magnetic recording media, by recording a specific signal and reproducing the recorded signal by means of two pairs of magnetic recording and playback heads arranged opposite one another and perpendicular to the plane of the recording medium, the ratio of the distance between the individual magnetic heads of each pair of heads to the wavelength of the recorded signal being within a specific range, and the said distance being such that a magnetic recording medium is movable symmetrically between the pair of heads, a common measuring unit being associated with the playback pair. Further features of the device relate to the design of the magnetic recording and playback heads, the measuring unit and the rate at which the particular magnetic recording medium being tested moves between the pairs of heads.

Abstract: An improved inductive loop structure useful for detecting metal objects such as vehicles on a roadway. The two terminal loop is formed by a conductive wire configured to define two substantially rectangular paths lying side by side in a common plane such that respective sides of the two paths lie adjacent one another. Alternating current is supplied to the terminals of the wire to produce a commonly oriented magnetic field around the adjacent sides of the rectangular paths and an oppositely oriented magnetic field of lesser magnitude around each of the outer sides of said rectangular paths. As a consequence, the field components interact to enhance field strength within the area bounded by said outer sides and reduce field strength outside of that area.

Abstract: An electromagnetic field which nutates about a pointing vector is used to both track or locate a remote object in addition to determining the relative orientation of the object. Apparatus for generating such a field includes mutually orthogonal dipole radiators, defining a reference coordinate frame, and circuitry for supplying excitations, such that the maximum intensity vector of a vector field produced by these excitations in the radiators nutates about a mean axis or axis of nutation which is called the pointing vector direction of the field. A pointing coordinate frame has the x-axis coincident with the pointing vector and the y-axis in the x-y plane of the reference frame. Mutually orthogonal sensors at the object sense the field and establish a sense coordinate frame, which can be coincident with the coordinate frame of the remote body.

Abstract: A system for detecting an AC magnetic field of a desired frequency using a magnetic sensing element of the parametrically excited second harmonic oscillator, in which a reference signal having a repetition period substantially equal to the repetition period of the AC magnetic field is adopted for synchronous detection of the detected output of the magnetic sensing element, and in which a current proportional to the intensity of a noise magnetic field is applied to the oscillation winding of the magnetic sensing element to lessen the influence of the noise magnetic field to greatly improve the SN ratio of the detected signal.

Abstract: A number of magnetic and memory signatures are developed for defining the equacy of a coated substrate for memory wire applications. The signatures are determined from sets of films on substrates which characterize good wire and can be used to separate the marginally good from the marginally poor substrate by applying tests at selected steps in the processing of newly coated wire. Separate signatures are established by omitting steps or varying combinations of steps in conventional plating processes and then measuring the magnetic or memory properties from section to section or from bit to bit along the wire.

Abstract: The magnetic gradient detector has two magnetic field sensors with their magnetic axes arranged parallel to an imaginary line. The sensor electrical outputs are connected with one another such that an electrical signal is created corresponding to the gradient of the magnetic fields present at the respective locations of the sensors. Each sensor has its core suspended on a wire under tension which maintains the parallelism constant. The wires are adjustable to establish initial parallelism or correct for subsequent misalignment that may occur.

Abstract: In measuring mechanical stresses in an object of hardened and tempered steel with a magnetic transducer of the type which comprises a magnetizing circuit for generating a magnetic field in the object and a measuring circuit for sensing the changes in the magnetic field which occur in the object when it is subjected to mechanical forces, in order to reduce the creep of the measuring signal which occurs in the case of continuous feeding, the magnetizing circuit is energize with energy in the form of AC pulses of a pulse length between 20 and 120 milliseconds.