Abstract: An inductive displacement detector of a rotary type is disclosed, which includes a first flux coupling winding and a second flux coupling winding alternately arranged on a rotor. The first flux coupling winding has a line conductor crossed. The second flux coupling winding has a line conductor not crossed. In the first and second flux coupling windings the transmission conductors thereof share a side.

Abstract: A rotation detecting device includes a rotary member having teeth, a biasing magnet, a magnetic sensor unit and a differential amplifier circuit for providing an output signal Vd. The sensor unit includes four bridge circuits of magnetoresistive elements that provide voltage signals V1, V2, V3, V4. The differential amplifier circuit includes a first differential amplifier for providing a first signal that is a difference between the voltage signals V1, V2, a second differential amplifier for providing a second signal that is a difference between the voltage signals V3, V4, a first circuit for providing a first amplified signal of the first signal amplified by a variable gain ?, second circuit for providing a second amplified signal of the second signal amplified by a fixed gain and a third differential amplifier for providing the output signal Vd by a difference between the first amplified signal and the second amplified signal.

Abstract: A rotation angle detecting device includes a magnet (4), a magnetic substance unit (5), and a non-contact magnetic detection element (7). The magnet (4) rotates with an object to be measured and includes two ends magnetized so as to have opposite polarities. The magnetic substance unit (5) forms a predetermined air gap with the two ends of the magnet (4) and is divided into magnetic members (6) so as to provide plane symmetry with respect to a vertical plane perpendicularly crossing a rotational center axis of the magnet (4) to form a magnetic detection gap (9) by the division. The non-contact magnetic detection element (7) is provided in the magnetic detection gap (9) between the magnetic members (6) so as to output a signal corresponding to a density of a magnetic flux passing through the magnetic detection gap (9). The rotation angle of the object to be measured is detected based on the output signal from the magnetic detection element (7).

Abstract: An eddy-current probe according to the present invention comprises: a substrate having a first surface facing to a subject to be tested and a second surface opposite to said first surface; an exciting coil formed on the second surface, having a pair of current lines in parallel with each other through which exciting currents flow in opposite directions to each other during testing, for generating an alternate magnetic field applied to the subject by the exciting currents; and at least one eddy-current sensor positioned on a central axis between the pair of current lines on the second surface of the substrate, for detecting a magnetic field generated newly from the subject by an eddy-current induced by the alternate magnetic field.

Abstract: A system and method for locating a horizontal bore below a ground surface includes a transmitting source configured to radiate from the bore a dipole magnetic field aligned with the bore. A receiver is located remote from the transmitting source and has a first coil and a second coil. Each coil defines an axis, wherein the axes of the first coil and the second coil are orthogonal to each other. A measurement device is in communication with the coils and configured to measure the phase of signals induced on the coils by the magnetic field when the axis of the first coil is horizontally perpendicular to the axis of the magnetic field and the axis of the second coil is vertically perpendicular to the axis of the magnetic field. The measurement device is also configured to determine the lateral position of the transmitting source relative to the coils responsively to the phase of the signals on the first coil and the second coil.

Abstract: A magnetic field response sensor comprises an inductor placed at a fixed separation distance from a conductive surface to address the low RF transmissivity of conductive surfaces. The minimum distance for separation is determined by the sensor response. The inductor should be separated from the conductive surface so that the response amplitude exceeds noise level by a recommended 10 dB. An embodiment for closed cavity measurements comprises a capacitor internal to said cavity and an inductor mounted external to the cavity and at a fixed distance from the cavity's wall. An additional embodiment includes a closed cavity configuration wherein multiple sensors and corresponding antenna are positioned inside the cavity, with the antenna and inductors maintained at a fixed distance from the cavity's wall.

Abstract: A method of noncontact measuring the electrical conductivity of electrolytes using a primary measuring transformer includes placing the electrolyte in a sampler, exciting an alternating magnetic field using an axisymmetrical eddy current sensor, switching to the sensor a capacitor of variable capacitance, tuning of the formed circuit in resonance with the frequency of the generator of harmonic oscillations, and recording the change in the introduced active resistance of the parametric eddy current sensor rated against its own inductive resistance.

Abstract: A photo magnetic field sensor includes a Faraday rotator made of a paramagnetic material, a polarizer, an analyzer, a light-irradiating element, and a light-sensing element. The Faraday rotator is made of a paramagnetic garnet single crystal including at least Tb and Al.

Abstract: A position transducer device is provided for detecting the position of a position transmitter. The position transducer device comprises a housing extending in a longitudinal direction and a measuring sensor arranged in the housing and extending parallel to the longitudinal direction. The position transmitter is coupled to the measuring sensor in a non-contacting manner. The outer surface of the housing is designed such that it can be enclosed at least partially by a fixing receiving means for fixing the housing to an application. The housing can be rotated relative to the position transmitter in the fixing receiving means in order to enable adjustment of the distance between the measuring sensor and the position transducer.

Abstract: In a position detecting apparatus 1 of the present invention, magnetic resistance circuits A and B of a first main circuit 10 include a reference magnetic resistance element +A, an even harmonic correction magnetic resistance element +A3, being placed at a position shifted by (1/4)? or (3/4)? from the reference magnetic resistance element +A, with respect to a reference wave, and a third harmonic correction magnetic resistance element +A2, being placed at a position shifted by (1/6)? from the reference magnetic resistance element, with respect to a reference wave, and magnetic resistance circuits A? and B? of a second main circuit 20 include the magnetic resistance circuit of the second main circuit 20 includes a reference magnetic resistance element +A?1, a fifth harmonic correction magnetic resistance element +A?2, being placed at a position shifted by (1/10)? from the adjacent magnetic resistance element, with respect to a reference wave and a fifth harmonic correction magnetic resistance element +A?2, bei

Abstract: Disclosed is a magnetic field sensor of high sensitivity, and which is power-saving and can be manufactured with low cost in a very small size. The magnetic field sensor includes a soft magnetic core formed to construct a closed-magnetic circuit on a semiconductor substrate, a magnetic field sensing coil formed by a metal film in a shape that winds the soft magnetic core, and a drive line for exciting the soft magnetic core by directly applying an electric current thereto. The drive line is formed in a rectangular angle to the magnetic field sensing coil, and connected to the both ends of the soft magnetic core in a length direction.

Abstract: A magnetic field strength detector includes a magnetic field sensing element that outputs voltage as a function of magnetic field strength. In some embodiments, the magnetic field sensing element comprises a coil, and voltage is induced across the coil as a function of the magnetic field strength. A magnetic field strength detector also includes an indicator that alters as a function of the voltage output by the magnetic field sensing element when the magnetic field strength exceeds a threshold. The alteration is substantially irreversible and, in some embodiments, visible. The detector may be used to, for example, measure the strength of a magnetic field generated by a degaussing device, or to confirm that a particular medium was exposed to a magnetic field with a strength adequate to degauss the medium.

Abstract: A debris sensor arrangement is positioned within an enclosed body of fluid for detecting the presence of metallic debris particles therein. Debris detection involves exposure of cantilever beams to the fluid when magnetized within an electromagnetic field to attract the metallic debris particles thereon and induce vibratory motion thereof at a resonant frequency varied by changes in the density of the debris particles magnetically held thereon. Measurement of the resonance frequency reflecting the density of the debris particles within the fluid being tested thereby monitors the corresponding wear of machinery reflected by the debris density.

Abstract: A method and system for detecting a position of a metallic object are disclosed. The method includes (a) exciting a coil with an electrical signal to produce an electromagnetic field enveloping the object, (b) allowing a frequency of the electrical signal to be at the resonant frequency of the coil as affected by the object, and (c) adjusting a control signal controlling a characteristic of the electrical signal so that the characteristic substantially equals a predetermined standard level. The method further includes (d) periodically coupling and decoupling a resistive element in parallel with the coil while performing (a)–(c), and (e) deriving a signal based upon the control signal. The derived signal is indicative of a difference between first and second values of an intermediate signal functionally related to the control signal, which are obtained when the resistive element is coupled in parallel with the coil and decoupled, respectively.

Abstract: A transducer (10) for distance measurement, especially between a stator and a rotor in a refiner for paper pulp production, in which the transducer is of the magnetic type and has a tubular casing (17), the one end of which forms a measuring head (14), in which a measuring pole (15) is fitted in a holder (16) which is mounted in the end of the casing (17) and seals this. The holder (16), with a first portion (22) of its axial length, reaches beyond the end of the casing. This first portion (22) and the measuring pole (15) are intended to be able to be worn away to a smaller axial length during use of the transducer, whilst the length of the casing is maintained.

Abstract: A modified hybrid Hall effect device is provided which is the combination of a conventional Hall effect device and a second Hall effect device having a Hall plate coupled to a ferromagnetic layer. The hybrid Hall effect device can be used to determine the independent magnetic field vector components comprising a vector magnetic field, such as for determining the x and the z components of a magnetic field, or for measuring the total magnitude of a vector magnetic field of any orientation. The modified Hall Effect device can be adapted for use as a magnetic field sensor for the detection of macroscopic objects that have associated magnetic fields, or for microscopic objects that have been tagged by microscopic magnetic particles. In one specific form, a plurality of hybrid Hall devices are electrically connected together to form an array in which a plurality of rows of hybrid Hall devices are electrically coupled to each other along a current axis, and the array is used for the detection of microscopic objects.

Abstract: A system and methods for an interface for magnetic sensors to determine a rotational angle has been achieved. This interface can be used for magnetic sensors providing analog signals of the sine and cosine values of the angle to be determined. Analog signals are being processed in two measurement paths for the sine and cosine signal each until the desired angle is computed by a CORDIC processor. The first stage of the measurement path is the conversion of the sine and cosine signals from analog to digital by 2nd order delta-sigma modulators with an over-sampling ratio. A low-pass decimation filter with sinc3 characteristic performs the digital value computation. The next stage normalizes the digitized sine and cosine values to correct offset and scaling deviations.

Abstract: A method for identifying a problem with a magnetic disk, comprising testing both sides of a disk for read errors using a pair of heads, flipping the disk 180 degrees, again testing both sides of the disk for read errors using the same heads, determining whether one side of the disk has more errors than the other side both before and after the flip, and determining that the disk is the cause of the read errors if the same side of the disk still has more errors than the other side after the flip.

Abstract: Provided herein is a xylophone bar magnetometer (XBM) with automatic resonance control, the XBM having a voltage input, a current drive input and a sensor output, having a voltage input switch for switching between a positive drive voltage and a negative drive voltage; a voltage controlled oscillator (VCO) for controlling the voltage input switch; and a feedback loop, connected between the sensor output and a input of the VCO.

Abstract: A magnetic head and disk tester comprises a base, a spindle for rotationally supporting a magnetic disk, a carriage for supporting a magnetic head support which carries a magnetic head with a magnetic read/write element, and a dual-stage positioning system that moves the carriage in two perpendicular directions X and Y. The magnetic head support, the magnetic head and the magnetic read/write element have a common longitudinal axis Z. The head support is positioned such that the longitudinal axis Z forms a predetermined angle between 0° and 90° with respect to the Y direction. Preferably the predetermined angle is about 45 degrees. When the head is driven from one point of an inner track to a point of an outer track, the displacement of the head along X axis is relatively large and the displacement of the head along Y axis is relatively small.