Abstract: A device rotates at least one static magnetic field about an axis, producing a rotating magnetic dipole field, and is movable in relation to the surface of the ground. The field is periodically sensed using a receiver to produce a receiver output responsive to the field. A positional relationship between the receiver and the device is monitored using the output. In one aspect, changing the positional relationship, by moving the device nearer to a boring tool which supports the receiver, causes an increase in accuracy of depth determination. In another aspect, determination of an actual overhead position of the boring tool, and its application, are described. Use of a plurality of measurements over at least one-half revolution of each magnet is disclosed. Establishing a surface radial direction toward a boring tool and resolution of multi-valued parameters is described. Calibration techniques, as well as a three transmitter configuration are also described.

Abstract: A semiconductor device includes: a detection Hall element for detecting a magnetic field; a temperature monitor Hall element; and a calculation circuit. The detection Hall element has a characteristic, which is almost a same as the temperature monitor Hall element. The detection Hall element is disposed near the temperature monitor Hall element. The detection Hall element outputs a Hall voltage. The temperature monitor Hall element includes a pair of driving signal supply terminals for outputting a temperature monitor voltage. The calculation circuit calculates to cancel a temperature characteristic of the Hall voltage based on the Hall voltage and the temperature monitor voltage.

Abstract: A method and system for measuring formation resisitivity is achieved by introducing an electrical signal into the formation. The current of the introduced electrical signal is then sensed, producing an analog voltage signal as a measurement of the formation. The introduced electrical signal is compared with the measured signal of the formation. The comparison is made in a quadrature demodulation device, producing an in-phase demodulated signal. A quasi-direct-current signal is extracted from the in-phase demodulated signal, producing an analog measurement related to the resistivity of the formation.

Abstract: A velocity-detecting device is mainly based on detection of charge, including a circuit board provided thereon with at least two capacitance sensors with potential difference. The two capacitance sensors are provided at different locations for detecting the time difference when a living thing moves and has its charge respectively reaching the critical one preset by the two capacitance sensors for calculating the moving velocity of the living thing, able to detect and calculate the moving velocity of a living thing for carrying out relative reaction to a machine.

Abstract: There is disclosed a base member for holding, without screws, a printed circuit board having conductive traces and electronic components and which can fit into an electric outlet box. The base member has walls which define a cavity where at least one wall of the cavity has a rib, the top of which functions as a stop for the printed circuit board. A cap having snap features adapted to engage the walls of the cavity restricts removal of the printed circuit board when snapped into position on top of the printed circuit board. The cap conceals the electronics on the printed circuit board and has at least one rib on its bottom surface to apply pressure to the printed circuit board assembly to help hold it in place. An aperture in the cap provides access to a pin header which is electrically connected to the printed circuit board. A screw terminal block is provided to connect the terminals on the pin header to a sensor.

Abstract: A system senses the position of a movable element in a mechanical apparatus. The element moves along an elongated guide member, which is at least partially formed of a magnetic material. An excitation coil is positioned by the guide member and a sensing coil moves with the movable element. An excitation circuit energizes the excitation coil and a position sensing circuit sense a voltage or current in the sensing coil to determine the distance between the coils.

Abstract: The invention relates to an inductive proximity sensor with a sensor element which includes a resonant circuit which provides an output signal which depends on the damping by an electrically conductive object. In accordance with the invention, the inductive proximity sensor has a ?? modulator for the evaluation of an output signal of the resonant circuit. The invention furthermore relates to a method for the determination of the presence and/or of the spacing of a metallic object with the help of an inductive proximity sensor.

Abstract: A position-sensing system magnetically senses the position of a piston rod moving with respect to a cylinder. A magnetically hard layer on the piston rod provides a recording medium. A track comprised of a plurality of magnetized regions is magnetized in the magnetically hard layer. A plurality of magnetic-field sensors is coupled to the cylinder in proximity of the magnetically hard layer to sense the magnetized track while the piston rod is moving with respect to the cylinder. A first one of the magnetic field sensors is positioned over the track to sense the magnetized regions of the track serially and a second one of the magnetic field sensors is positioned radially to one side of the track. The magnetic field sensors generate signals, in response to sensing the magnetized regions, for use in measuring rotational movement of the piston rod.

Abstract: A method of biasing a magneto resistive sensor element includes providing at least one magneto resistive sensor element having a magnetic sensitivity along a first axis that is parallel to a plane of the at least one sensor element. A magnet is positioned adjacent to the at least one sensor element for biasing the at least one sensor element, wherein the magnet has a magnetization that is non-perpendicular to the plane of the at least one sensor element, and wherein the magnetization includes a component parallel to the plane of the at least one sensor element that increases a sensitive range of the at least one sensor element along the first axis.

Abstract: A receiver streamer system for marine electromagnetic surveying includes a first streamer, and a second streamer disposed substantially parallel to and spaced apart from the first streamer. A first pair of electrodes is associated with the first streamer and a second pair of electrodes is associated with the second streamer. Each of the first and second pairs of electrodes is functionally associated with a voltage measuring circuit configured to measure voltage along an inline direction. At least one electrode on each of the first and second streamers is configured and associated with a voltage measuring circuit to make voltage measurements in a cross-line direction.

Abstract: A gobo wheel with automatic detection system that automatically detects a rotational position of the gobo. The rotational position can be detected by a magnetic marking system. Each of the gobos can be randomly placed within the holder. the position of the gobos can be automatically determined during a start up routine for example, and then those positions can be stored and used for later determination of a position.

Abstract: A method of inspecting a test part is provided. The method includes positioning an eddy current probe on a surface of the test part and scanning the test part using the eddy current probe to generate a first signal corresponding to a no lift-off condition of the test part. The method further includes positioning the eddy current probe at a pre-determined distance from the surface of the test part and scanning the test part using the eddy current probe positioned at the pre-determined distance from the test part to generate a second signal corresponding to a lift-off condition of the test part. The method also includes processing the first and second signals to estimate an electrical conductivity of the test part.

Abstract: Methods are provided for calibrating a tachometer or generator device to reduce residual errors associated with the tachometer-generator device. A shim structure is positioned within the air gap of the tachometer-generator device. A physical characteristic or location of placement of the shim structure is selected to reduce variation in an output voltage of the tachometer-generator device.

Abstract: The invention concerns a device and a method for examining magnetic properties of objects, in particular of sheet material such as for example bank notes. Therein the invention proceeds from a device and a method for examining magnetic properties of objects with a magneto-optical layer having magnetic domains, the optical properties of the magneto-optical layer being influenced by the magnetic properties of the object to be examined, at least one light source for the generation of light incident upon the magneto-optical layer, and at least one sensor for the reception of light which is transmitted and/or reflected by the magneto-optical layer, with a magnetic filed in the area of the magneto-optical layer which extends substantially parallel to the surface of the magneto-optical layer.

Abstract: A method for producing a coil assembly includes overlaying printed circuit traces on a core. The traces include terminals for coupling to conductive connections on a base on which the coil assembly is to be mounted. Two or more wires are wrapped around the core so as to define two or more coils, wrapped in different, respective directions. The ends of the wires are coupled to the printed circuit traces, so as to connect the wires through the traces to the terminals.

Abstract: An exemplary metal detector includes a detecting circuit, a SCM, a converting circuit, and a cymometer. The SCM cooperates with the detecting circuit to generate a current signal with a specific frequency, the converting circuit transforms the current signal received from the SCM to a voltage signal, and the cymometer displays a value of a frequency of the current signal according to the voltage signal. When the detecting circuit detects a metal nearby, the value of the frequency of the current signal displayed on the cymometer changes.

Abstract: A magnetic sensor assembly (100) uses printed circuit boards (PCB) (102) having a first surface (130) and an opposite, complementary second surface (132) to fabricate the sensor devices (104) and their associated processing circuitry. A trace or conductive element (106), or pair (108a, 108b) of complementary printed traces or conductor elements, on or within the board (102) are run beneath the magnetic sensor element (104), with the return trace or traces routed more remotely from the sensor (104).

Abstract: A variable inductance position sensor is described. The sensor includes a housing that is typically cylindrical in shape. The housing includes an open end and a closed end forming a cavity therein. A coil support member is affixed at one end to the closed end of the housing, or the coil support member may itself seal the housing at the closed end. The coil support member includes a coil assembly that includes a coil both of which are rigidly affixed to the coil support member. In this way, the coil is maintained in a fixed and predetermined orientation with respect to the housing. The combination of housing, coil support member and coil assembly and the coil forms an inner assembly. The coil support member includes a bore that forms a central annular region and the coil support member then forms an outer annular region as well. In addition, the housing may also include a passageway to allow the passage of lead wires from the coil assembly to the exterior of the sensor.

Abstract: A method for drilling substantially parallel twin wells includes drilling a first well and deploying a casing string in the first well. A magnetized section of the casing string includes a plurality of magnetized wellbore tubulars having at least one pair of opposing magnetic poles located between longitudinally opposed ends of the wellbore tubular. A portion of a second well is drilled within sensory range of magnetic flux from the magnetized section of the casing string. The local magnetic field is measured in the second well and processed to determine a direction for subsequent drilling. Drilling proceeds along the direction for subsequent drilling.

Abstract: A method for magnetizing a wellbore tubular is disclosed. The method includes magnetizing a wellbore tubular at three or more discrete locations on the tubular. In exemplary embodiments the magnetized wellbore tubular includes at least one pair of opposing magnetic poles located between longitudinally opposed ends of the tubular. Wellbore tubulars magnetized in accordance with this invention may be coupled to one another to provide a magnetic profile about a section of a casing string. Passive ranging measurements of the magnetic field about the casing string may be utilized to survey and guide drilling of a twin well. Such an approach advantageously obviates the need for simultaneous access to both wells.