Abstract: A rotational angle sensor detects a rotational angle of a rotary member based on a magnet field produced across the rotary member by a pair of magnets. At least one magnetic detection device is disposed within a holder and serves to detect the magnetic field and to output a signal representing the rotational angle of the rotary member. For example, the holder may be mounted to a fixed place. A printed circuit board is coupled to the holder and is electrically connected to the at least one magnetic detection device. A positioning device serves to position the at least one magnetic detection device in a predetermine position relative to the holder.

Abstract: An electromagnetic prober comprising a transmission antenna, a reception antenna, a reception signal processing section for generating an analytic signal on the basis of a detection signal of the reception antenna, and an analytic processing section for performing a predefined analytic process on the basis of the analytic signal, wherein the analytic processing section divides the analytic signal into a plurality of time-based ranges and performs a predefined computation on average cycle periods in the respective time-based ranges of the analytic signal to calculate average dielectric constants in depth ranges of the medium corresponding to the respective time-based ranges.

Abstract: A multirotation type encoder of the invention includes a first encoder 20 attached to a rotating shaft 11 of a rotating machine 10 for detecting an absolute value rotational angle within one rotation, and a second encoder for counting a multirotation amount of the rotating shaft 11 by using a speed reducing mechanism 30 by magnetic coupling and the second encoder 40 is constituted by a first magnetic gear 31 directly connected to the rotating shaft and magnetized in multiple poles and at least one second magnetic gear 32 arranged to be opposed thereto in noncontact and magnetized in multiple poles by a number of magnetic poles larger than that of the first magnetic gear 31 and is constituted to count a multirotation amount by detecting a rotational angle of the second magnetic gear by the second encoder.

Abstract: A sensor circuit includes a sensor element, a current source for supplying an operating current for the sensor element and an amplifier circuit for amplifying a sensor voltage produced by the sensor element when applying the operating current, wherein the amplifier circuit has a resistor influencing the amplification of it. The resistor of the amplifier current and the sensor element are formed equally as regards technology so that variations, due to technology, of the sensor sensitivity of the sensor element are counteracted by an amplification factor of the amplifier circuit changing in the opposite way.

Abstract: A system for detecting or determining the nature of a subterranean reservoir. An electromagnetic field is applied using a dipole antenna transmitter and this is detected using a dipole antenna receiver. The measurements are taken with the antenna both in-line and parallel and the difference between the two sets of measurements is exploited. A characteristic difference indicates a high resistive layer, which corresponds to a hydrocarbon reservoir.

Abstract: A device and method is taught for detection of flaws and localized wall loss in pipes made of ferromagnetic-based material. The device utilizes a magnetic field generator to create a horizontal magnetic field of flux. A pipe is passed through the magnetic field where a magnetic fluctuation detector, for example multiple groups of hall units, identifies fluctuations in the magnetic field.

Abstract: A method and system of operating an electromagnetic resistivity tool wherein at least one transmitting antenna of the tool is selectively operable at three or more resonant frequencies for better resistivity profiling of a formation.

Abstract: A magnetic field sensor for measuring at least two components of a magnetic field comprises a ferromagnetic core mounted on a semiconductor chip, an exciter coil to which a current can be applied and two read-out sensors. The ferromagnetic core is ring-shaped. The exciter coil is preferably formed from conductor tracks of the semiconductor chip and from bonding wires.

Abstract: In a displacement sensor (10), a shaft (24) of a movable member (14) comprises a tubular part (26) having an opening (26c) at one end. A rod-form permanent is inserted into the tubular part (26) through the opening (26c) . A spacer (32) is fitted over a narrow portion of the rod-form magnet (28). The thickest portion of the magnet (28) and the spacer (32) contact the side wall of the tubular part (26) tightly, so that the magnet (28) is disposed coaxially with the tubular part (26). A stopper (26d) is formed on the opening (26c) of the tubular part (26), so that the magnet (28) does not move axially. Therefore, the magnet (28) is mounted in a prescribed position in a movable member (14) with a high degree of accuracy.

Abstract: An apparatus is disclosed for measuring formation resistivity through a conductive pipe in a wellbore. The apparatus includes a sonde adapted to be moved through the wellbore, and a plurality of voltage measurement electrodes are disposed on the sonde at spaced apart locations. At least one current source electrode is disposed on the sonde. All the electrodes are adapted to make electrical contact with the pipe. The apparatus includes a digital voltage measuring circuit controllably coupled to selected ones of the voltage measurement electrodes and digitally controlled current sources.

Abstract: Described are systems of recording piston rod position information in a magnetic layer on the piston rod. A piston rod moving with respect to a cylinder has a magnetically hard layer formed thereon to provide a recording medium. A magnetic pattern is recorded in the magnetically hard layer. A magnetic field sensor senses the recorded magnetic pattern while the piston rod is moving with respect to the cylinder and generates signals in response to the magnetic pattern that are used to determine an instantaneous position of the piston rod.

Abstract: In a rotational angle detecting device, an auxiliary magnet is disposed so as to surround a Hall element around the Z-axis, so that variation of offset magnetic flux is suppressed even when the position of the Hall element is displaced in the X-axis direction with respect to the auxiliary magnet. In addition, even when the fabrication position of the Hall element is displaced in the Y-axis direction of the auxiliary magnet, the variation of the offset magnetic flux is suppressed. By adjusting the dimension (the length in cylinder direction) in the Z-axis direction of the auxiliary magnet, the variation of the offset magnetic flux is suppressed even when the Hall element is displaced from the center of the auxiliary magnet in the Z-axis direction. That is, even when the position of the Hall element is displaced from the center of the auxiliary magnet in the three-dimensional direction, the displacement of the offset magnetic flux can be prevented, and thus reduction of the detection precision can be prevented.

Abstract: The invention relates to a path and/or position measuring device (1) comprising a magnet (2) and a sensor (3) detecting the magnetic field intensity. The magnet (2) and/or the sensor (3) co-operate with a movable element (4), it being possible for a relative movement between the sensor (3) and the magnet (2) to be brought about by means of the movable element (4). Furthermore, the magnet (2) is formed in such a way that the magnetic field intensity varies along an axis (5) of the magnet (2) and is not constant. The relative movement is substantially in the direction of this axis (5) of the magnet (2). The path and/or the position of the movable element (4) can be determined on the basis of the magnetic field intensity detected by the sensor (3).

Abstract: A device for measuring the angle of rotation of a rotating member of a machine, comprising a signal transmitting rotor which includes a magnet rim consisting of magnets having alternatingly arranged south poles and north poles and being moved with respect to a stationary measuring sensor is characterized in that each magnet or each magnet zone has a thickness which varies substantially sinusoidally in circumferential direction, having its maximum in the pole center of each magnet and/or forms an air gap with the measuring sensor varying sinusoidally in circumferential direction.

Abstract: Methods and systems are disclosed in which the errors caused by thermal expansion in magnetoresistive position transducers are reduced by predicting the physical alterations over temperature between centerline-to-centerline distances of particular magnetoresistive sensors or components within a magnetoresistive array and also between such an array and a magnet being sensed caused by thermal expansion.

Abstract: A variable reluctance-type resolver which does not deteriorate detecting accuracy, and which can fix the rotor to the rotate shaft cheaply is comprised of a stator 5 on which coils 6 are wound, a rotor provided with protrude poles 4a and an annular stopper 10 made of magnetic material. An outer diameter DS of the stopper 10 is selected to be smaller than a valley diameter DR of the rotor 4. Leakage of the magnetic flux from the stator to the stopper is prevented, and the stopper made of the magnetic material can fix the rotor in cheaper way.

Abstract: A magnet is provided to one of two members, which make relative rotation therebetween. First and second Hall elements are arranged adjacent to each other and are provided to the other one of the two members. A magnetic sensing surface of the first Hall element is generally perpendicular to a magnetic sensing surface of the second Hall element, and a relative rotational angle between the two members is determined through the first and second Hall elements based on a magnetic flux, which is generated by a magnetic flux generating portion of the magnet and passes through the first and second Hall elements toward a magnetic flux attracting portion of the magnet.

Abstract: A measuring graduation for position measuring systems has a base body formed of a permanently magnetizable material, extending in a measuring direction and having first and second sections alternatingly arranged one after another in the measuring direction and having, respectively, first and second magnetization directions, with the second sections being formed by magnetically weak regions, and with the second magnetization direction of the second sections being defined by the first magnetization direction of adjacent first sections; and the method of magnetization of the base body includes magnetizing the base body in a homogenous outer magnetic field.

Abstract: Apparatuses and methods for monitoring microfeature workpiece rotation during processing, such as brushing, by monitoring characteristics corresponding to a state of a magnetic field proximate to the rotating microfeature workpiece are disclosed herein. The characteristic can depend on the relative motion between the magnetic field and the conductive material of the microfeature workpiece. The characteristic can include the strength of the magnetic field, current in an electromagnet circuit used to create the magnetic field, force exerted on the magnetic field source, or movement of the magnetic field source. The apparatus can include a feedback control device to adjust the rotation speed of the microfeature workpiece based on the characteristic detected.

Abstract: An apparatus for locating a buried utility conveyance, such as an undersea cable, beneath a body of water. The apparatus generally comprises a submersible housing that contains a variable ballast system for selectively controlling the buoyancy of the apparatus, operator-controlled maneuvering apparatus, and a detector assembly for locating the conveyance. The detector assembly includes first and second signal generators and first and second signal detectors for vectoring the location of the conveyance. An operator guides the detector relative to a target search location through cables attached to the housing and the variable ballast system. A camera generates images of the target search location for use by the operator to control the apparatus through an umbilical cable connected to the housing.