Abstract: An inductive displacement or rotational angle sensor including at least one electrical coil which is provided with turns, and an influencing element which interacts with said coil and produces a different inductance of the least one coil as a function of its position, characterized in that at least two separate coils which are arranged coaxially with respect to a coil axis and have an axial interspacing are provided, it being possible for the influencing element to enter said interspacing with a degree of overlap, which is dependent on its position, with the magnetic fields which are generated by the coils.

Abstract: An induction sensor generates speed data based on a frequency of the change in magnetic flux within the sensor and powers sensor circuitry by recharging a power source using at least a portion of the electrical voltage induced by the change in magnetic flux. In this manner, the induction sensor may generate its own power to sense and transmit data. To optimize the recharging power available from the induced electrical voltage, the sensor may also include a variable load. This variable load may be automatically controlled by the sensor based on the induced voltage and/or current. The induction sensor may also wirelessly transmit generated data. In addition, the sensor may, after shutting down, automatically power up in response to the change in magnetic flux exceeding a start-up threshold.

Abstract: In one aspect of the present invention a method of determining a distance to a ferrous material comprises providing a plurality of magnetometers spaced at varying distances from a ferrous material, detecting a ferrous material with each of the plurality of magnetometers individually, establishing one of the plurality of magnetometers as a primary magnetometer, obtaining sensor readings from each of the plurality of magnetometers, forming a first ratio of the differences in the sensory readings of the primary magnetometer to the sensory readings of the other magnetometers, forming a second ratio of the differences in inversely cubed distances to the ferrous material from the primary magnetometer to inversely cubed distances to the ferrous material from the other magnetometers, setting the first ratio and the second ratio equal to each other, and calculating the distance to the ferrous material from the plurality of magnetometers.

Abstract: A magnetic angle sensor system for determining a shaft angle for one or more pivoting or rotating shaft means. The or each of said shaft means is provided with means adapted to generate a magnetic field, such that means can be energised in turn to induce a magnetic field in a detector. In a first step the sensor arrangement measures the background field in the absence of any current in the wire or solenoid, such that the angle of the shaft means can be determined from the magnetic field in the solenoid and the background field. The invention concerns the use of an evoked response field whether alternating or steady whereby the angle is determined by the difference in field when the evoking magnetic stimulus is present from when it is absent.

Abstract: Coils are formed into a coil group for a single phase by serially connecting a plurality of coils so that the resulting magnetic flux distribution is a sine wave distribution. The coil group for a single phase is constituted by a plurality of coil sets, formed from two coils that are wound around two adjacent magnetic pole teeth, connected in series. Each coil set includes coils of the two magnetic pole teeth constituting that coil set wound in opposite directions to each other looking from the inside of the stator. An electrical wire extending from an end winding of each coil is turned back so as to run in a direction opposite to an electrical wire connection to a start winding of that coil, and is connected to either a start winding of the next coil or a connection terminal.

Abstract: A device for detecting the axial position of a rotary shaft of a rotary machine comprises a target of ferromagnetic material placed at the end of the rotary shaft, an induction coil associated with a stationary magnetic circuit and placed facing the target while leaving an airgap, and a power supply circuit. The power supply circuit comprises an AC voltage source connected between a first end of the induction coil and a zone situated at a reference voltage, at least one capacitor connected between the ends of the induction coil, and a detector device interposed between a second end of the induction coil and the zone situated at the reference voltage, in order to deliver on a line information about the magnitude of the current flowing between the second end and the zone situated at the reference voltage.

Abstract: An inductance-type rotation angle sensor includes: a stator formed by printing an annularly formed magnetic conductor and a receiving conductor placed adjacent to the magnetic conductor on a glass-epoxy-resin substrate; and a rotor having an excitation conductor attached thereto in a manner opposing the magnetic conductor. In the sensor, a thermosetting-resin covering layer, which is connected together through a periphery of the substrate and a through-hole included in this substrate, is formed on both front and back surfaces of the substrate by molding; a portion of the covering layer covering the magnetic conductor and the receiving conductor is formed as a thin thickness part which is thinner in thickness than a remaining portion of the covering layer; and the stator is buried in a thermoplastic-resin control housing with the thin thickness part being exposed to an outside.

Abstract: A wing flap sensor unit (2) having a position sensor (18) for detection of a rotation position of a shaft for operation of wing flaps and having a housing (4) which surrounds the position sensor (18), having an attachment component (20, 22) for attachment in an aircraft wing and having a connecting point (24) for an electrical connector of the position sensor (18). Hereby, the housing (4) is at least partially manufactured from titanium using a precision-casting method. The titanium precision-casting method makes it possible to achieve a particularly robust and lightweight housing.

Abstract: A device for measuring the position of a target includes a track, which includes a primary winding (513) supplied with an alternating current at high frequency, and a plurality of secondary windings (511, 512). The device measures the position of the leading edge (510) of the target (500) in a so-called longitudinal direction (5000) between a first position and a second position between which the target (500) completely covers the track (550). Surprisingly, this configuration enables a very significant increase in the useful measurement length of such a track (550).

Abstract: A sensor circuit for use with a shaft assembly rotatably mounted in a housing and having an input shaft, an output shaft and a torsion bar which connects the input and output shafts together. A CR coil mounted to the housing around the shaft assembly is energized and generates an electromagnetic field. An RX coil is mounted to and rotates with the shaft assembly and has an output connected to a power circuit to generate electrical energy when excited by the electromagnetic field from the first coil. The power circuit powers an angle sensor which transmits a signal back to the first coil representative of the angle between the input and output shafts.

Abstract: The present invention relates to an inductive proximity sensor that includes an oscillator having first and second inductor-capacitor circuits arranged such that an inductance of one of the inductor-capacitor circuits has substantially greater sensitivity to an external target than an inductance of the other inductor-capacitor circuit. The sensor also includes an alternating current drive to each of the inductor-capacitor circuits that is in-phase and depends on differences in voltage across the inductor-capacitor circuits. The sensor may be coupled to a calibration device that applies power and triggers a calibration routine within the sensor. In response to the trigger signal, a calibration processor within the sensor executes the calibration routine and adjusts the inductor-capacitor circuits and provides an indication of successful calibration.

Abstract: An angle detecting apparatus includes a rotor fixed to a rotating shaft, a pair of magnetic sensors arranged close to the outer periphery of the rotor so as to have a difference in angle (?/2) with respect to the center of rotation of the rotor, a differential operational circuit performing differential operation on detection signals output by the magnetic sensors to output a differential signal, and the angle calculating circuit calculating the angle of rotation of the rotating shaft based on the differential signal. The planar shape of the rotor is such that the sum of the distances between the center of rotation and the respective two points where two straight lines crossing at the center of rotation at a crossing angle of (?/2) cross the outer periphery of the rotor is constant, and the planar shape is symmetric with respect to a straight line passing through the center of rotation.

Abstract: The invention provides a transformer probe for sensing movement of a body of magnetic material, having multiple output channels wherein the output in each output channel is substantially unaffected by faults in other output channels.

Abstract: A SIN signal detection coil is divided into two parts in a circumferential direction and further into two parts in a radial direction so that a SIN-coil first part and a SIN-coil second part are arranged on an outer circumferential side and a SIN-coil third part and a SIN-coil fourth part are arranged on an inner circumferential side. The SIN-coil first part and third part are placed in the same position in the circumferential direction and to face each other in a radial direction. The SIN-coil second part and fourth part are placed in the same position in the circumferential direction and to face each other in the radial direction. The SIN-coil first part and fourth part are placed in the first coil layer. The SIN-coil second part and third part are placed in the second coil layer.

Abstract: The invention relates to a method for analysis of magnetic fields or signals used for the determination of the position of an object, wherein two temporally to each other shifted magnetic signals or fields are generated by two conductors arranged at least in part or completely separated from each other. The magnetic fields generated by the conductors are consecutively being captured by at least one and preferably three sensors arranged orthogonally to each other and determining from the captured signals information for determining the position of the object carrying the sensors relative to the conductors.

Abstract: Methods for accurately tracking position and orientation of a magnetic-field sensor in a tracking volume when a large magnetic-field distorter is present in the tracking volume. In some of the methods, magnetic field data is collected from within the tracking volume both with and without the large magnetic-field distorter present in the tracking volume. This data is used to obtain correction information that is subsequently used during real-time operation of the magnetic-field sensor to correct the position and orientation solutions for the sensor for magnetic-field distortions caused by the presence of the large magnetic-field distorter in the tracking volume. Others of the methods involve modeling the large magnetic-field distorter using dipole and multipole modeling. Magnetic tracking systems for implementing the methods include hardware and software for carrying out the methods.

Abstract: A robust method for detecting a relative position of a feedback device, such as an encoder or resolver, coupled to a shaft, such as a motor shaft, is provided. To detect the relative position, electrical commands are issued in an open loop mode to spin the motor shaft an amount greater than the apparent rotational angle between two consecutive markers of the position feedback device, such that the net mechanical rotation is equal to or greater than the total rotational angle between two consecutive markers.

Abstract: A non-contact sensor system is provided that comprises a first sensor element disposed on a stationary member, and a second sensor element disposed on a rotational member. The second sensor element is proximate the first sensor element without physically contacting the first sensor element. The rotational member is configured to facilitate selection of at least a first position and a second position, and the first sensor element and the second sensor element are operatively coupled to facilitate sensing of the selected position.

Abstract: Method for determining the position of a rotor in a brushless motor or in a stepper motor, said method including the following steps: applying a voltage in at least one powered phase of the motor; measuring, in an unpowered phase of the motor, the voltage induced by mutual inductance between phases; and determining said position and/or the speed of the rotor from said induced voltage.

Abstract: In one embodiment, a method for determining the distance of a conducting surface profiled in a direction of distance determination from a functional surface moving relative to the profiled surface is disclosed. The method includes connecting inputs of a sensor to an oscillator arrangement. The sensor includes a first and a second measuring coil. The method includes further connecting outputs of the sensor to an analog-to-digital converter via a demodulator unit to obtain first and second digital measured values. The first and second digital measured values correspond to the distance between the profiled surface and the first and second measuring coil of the sensor, respectively. The method further includes connecting an arithmetic unit to the analog converter unit. The second measurement coil is arranged at a known distance from the first measuring coil on the side of the first measuring coil that faces away from the profiled surface.

Abstract: An inductive proximity sensor and related method for sensing a presence/position of a target, with mounting effect compensation, are disclosed. In at least one embodiment, the method includes providing a proximity sensor having first and second coils that are both at least indirectly in communication with control circuitry. The method also includes receiving respective first and second signals at least indirectly indicative of respective first and second electromagnetic field components respectively experienced by the first coil as influenced both by a target and a structure supporting the sensor and the second coil as influenced by the supporting structure. The method further includes determining by way of the circuitry a third signal based at least in part upon the first signal, as modified based at least in part upon the second signal, whereby the third signal is indicative of the presence or position of the target relative to the sensor.

Abstract: An oscillator circuit outputs an oscillator signal with a frequency corresponding to an inductance of a displacement detector coil. An oscillation cycle measurement circuit measures a cycle of the oscillator signal output from the oscillator circuit, and outputs a signal corresponding to the measured cycle. A squaring circuit calculates and outputs a square of the signal output from the oscillation cycle measurement circuit. By the calculation and output of the square of the oscillator signal cycle, a square root component of the product of inductance and capacitance components is eliminated, so that the output signal changes linearly relative to the displacement of a displacement body. As a result, the linearity of the output signal relative to the displacement of the displacement body can be improved.

Abstract: A non-contact sensor system is provided that comprises a first sensor element disposed within a first member having an axis Y, and a second member configured to rotate about the axis Y at a value X. The second member is configured to interface with the first member. The non-contact sensor system further comprises a second sensor element disposed on the second member proximate the first sensor element without physically contacting the first sensor element, and the first sensor element and the second sensor element are operatively coupled to facilitate sensing the value X. The non-contact sensor system may be configured to sense velocity, acceleration, and other values.

Abstract: A sensor arrangement is provided for determining the current rotation angle position of a shaft with respect to a stationary reference point. In order to determine the rotation angle position without wear and tear and with little outlay on materials and little energy requirement during ongoing operation, the coil is arranged between the shaft and a stationary reference point in such a manner that at least one geometrical property of the coil can be changed over the range of rotation angle positions of the shaft. The changed geometrical property of the coil is used to determine the rotation angle position of the shaft.

Abstract: A proximity sensor includes an L-C resonator, an oscillator for oscillating the L-C resonator, an oscillation detector, an output circuit, and a burnout detecting means. The L-C resonator has a detection coil for detecting an object, and a resonant capacitor connected across the detection coil. The oscillation detector detects an oscillation of the L-C resonator. The burnout detecting means has a time counter for counting a length of a positive voltage period in which a voltage across the resonant capacitor is kept above a predetermined positive voltage, and a discriminator which determines burnout of the detection coil when the counted length exceeds a half of an oscillation cycle of the L-C resonator. The output circuit outputs a detection signal indicative of whether or not the object exists within a detection range of the detection coil, and provides a burnout signal indicative of the burnout of the detection coil.

Abstract: A position detecting system includes a magnetic field generator, a detecting body, a magnetic field detector, a position/direction calculating unit, and a control unit. The magnetic field generator generates a magnetic field in a three-dimensional space. The detecting body is put into the three-dimensional space, and includes a resonance circuit for generating a resonance magnetic field. The position/direction calculating unit calculates a position/direction of the detecting body. If the resonance circuit is in the non-resonant state, the magnetic field detector detects an environmental magnetic field, and the control unit updates detection data of the environmental magnetic field. If the resonance circuit is in the resonant state, the magnetic field detector detects the spatial magnetic field in the three-dimensional space. The position/direction calculating unit executes processing using the detection data of the spatial magnetic field and updated detection data of the environmental magnetic field.

Abstract: Methods, systems, and apparatus for optical imaging and patterning based on a magnetically controlled ferrofluid are described. One such system includes a substrate and an active region including multiple magnetic field generators. The active region is positioned adjacent to the substrate. The system includes a ferrofluid positioned on the substrate adjacent the active region within a range of a magnetic field of the multiple magnetic field generators. The ferrofluid is distributed across multiple ferrofluid regions. Each magnetic field generator is aligned with a corresponding ferrofluid region.

Abstract: Recovering metallic materials, such as copper, from waste materials. The dynamic sensor measures the rate of change of current generated by metallic materials in the waste materials. Preprocessing and post processing of the waste materials may be completed to further concentrate the amount the metallic materials recovered from the waste.

Abstract: In a resolver for determining the relative angular position between two subassemblies, each subassembly includes a winding, the winding being situated inside a housing made up of two housing shells. The housing shells have tabs which are oriented with an axial directional component and joined in interlocking manner with axial overlap at a mutual offset in the circumferential direction.

Abstract: An inductive position encoder is described having first and second members which are relatively moveable over a measurement path, a magnetic device mounted on the first member; a plurality of first windings mounted on the second member; and a second winding. The magnetic device is operable to interact with the windings such that upon the energization of either the second winding or the first windings, there is generated a plurality of sensor signals each being associated with a respective one of said first windings and varying with the relative position between said magnetic device and the associated first winding and hence with the relative position between said first and second members. Additionally, the plurality of first windings are arranged along said measurement path so that the sensor signals vary substantially in accordance with a predetermined Gray code.

Abstract: A linear position sensor having a transmitter coil which generates electromagnetic radiation when excited by a source of electrical energy and wound in a first direction. A receiver coil is contained within the transmitter coil and the receiver coil includes both a first loop wound in a first direction and a second loop wound in the opposite direction. A coupler element linearly moves along a first direction relative to the transmitter coil which varies the inductive coupling between the transmitter coil and the receiver coil as a function of the linear position of the coupler element to thereby vary the electrical output signal from the receiver coil when excited by the transmitter coil. The first and second loops of the receiver coil are linearly aligned with each other along the first direction.

Abstract: A multi-path data dissemination method for a magnetic diffusion wireless network and a system thereof overcome environmental interferences in wireless data transmissions. Each node of the network is provided for figuring out its good neighbors by broadcasting a good-neighbor exploratory message in a bootstrap process. Each node keeps a good-neighbor table containing nodes with a RSSI higher than a threshold of the good-neighbor table. A magnetic field of a magnetic diffusion (MD) dissemination method capable of determining a data dissemination path is created according to the good-neighbor tables to ensure that the data can be forwarded to a data sink successfully.

Abstract: A sensor device measures a property of an object. The sensor device comprises a magnetic field generator adapted to generate a magnetic field in at least a part of the object, and at least one magnetic field detector adapted to detect at least one detection signal in response to the magnetic field generated in at least a part of the object. The at least one detection signal is indicative of the property of the object. A direct current or a direct voltage is applicable to the magnetic field generator to generate the magnetic field in at least a part of the object.

Abstract: Systems and methods for sensing external magnetic fields in implantable medical devices are provided. One aspect of this disclosure relates to an apparatus for sensing magnetic fields. An apparatus embodiment includes a sensing circuit with at least one inductor having a magnetic core that saturates in the presence of a magnetic field having a prescribed flux density. The apparatus embodiment also includes an impedance measuring circuit connected to the sensing circuit. The impedance measuring circuit is adapted to measure impedance of the sensing circuit and to provide a signal when the impedance changes by a prescribed amount. According to an embodiment, the sensing circuit includes a resistor-inductor-capacitor (RLC) circuit. The impedance measuring circuit includes a transthoracic impedance measurement module (TIMM), according to an embodiment. Other aspects and embodiments are provided herein.

Abstract: In one aspect of the present technique, an array of electromagnetic sensors is positioned within a volume of interest. In the presence of an electromagnetic field, the array of electromagnetic sensors is sampled to acquire signals representative of the location of the electromagnetic sensors in the array. The electromagnetic field distortion within the volume of interest is determined based on the acquired signals. In another aspect of the present technique, a system for detecting electromagnetic field distortions includes an electromagnetic sensor assembly for positioning within a volume of interest, a plurality of electromagnetic sensors for transmitting or receiving signals representative of the location of the electromagnetic sensors on the sensor assembly; and a tracker. In another aspect of the present technique, an electromagnetic sensor assembly for detecting electromagnetic field distortion includes a body, and an array of electromagnetic sensors positioned on the body.

Abstract: A position detecting device is provided, which is configured to minimize leakage of magnetic flux in an electromagnetic induction system. The position detecting device includes: a sensor unit including a plurality of first loop coils arranged in a first direction and a plurality of second loop coils arranged in a second direction intersecting with the first direction; a yoke sheet provided on a side of the sensor unit that is opposite to a side that faces a position indicator; an auxiliary loop coil provided at a corner part of the sensor unit; a signal transmitter configured to transmit a signal to one of the coils in order to generate a magnetic field to induce an induced current in a coil of the position indicator; and a controller configured to select one of the coils, and to control whether to transmit a signal from the signal transmitter to the selected one of the coils or to make the selected one of the coils receive a signal from the position indicator.

Abstract: There is described a position sensor comprising a sensor electromagnetic field generator, a screen arranged to confine the sensor electromagnetic field, and an output. The output is arranged to provide a signal which varies in dependence upon an amount of flux compression of the electromagnetic field resulting from the presence of the screen. The amount of flux compression is related to a position of the screen in relation to the sensor electromagnetic field generator. There is also described a method of detecting a relative position of an electromagnetic field generator and a screen.

Abstract: A generally planar shaped inductor is disclosed that is particularly adaptable for use in motion or position sensors. One inductor can function as a signal input unit and another as a pick up unit in an arrangement wherein both inductors are placed in a generally parallel juxtaposition for flux flow there between. A movable armature is located between the inductors to control the amount of flux transmission between inductors. The position of the armature relative to the inductors controls the output signal generated by the pickup inductor that are adapted to be converted into indications of displacements.

Abstract: A method for non-contact measurement of multiple shaft parameters is provided. The method includes magnetically encoding multiple sections of the shaft using pulsed currents. The method also includes sensing a magnetic field of the encoded sections of the shaft using multiple sensors arranged circumferentially about the shaft. Further, the method includes generating a spectrum of periodical variations based on sensed magnetic field of the encoded sections of the shaft during rotation and determining multiple parameters based on recurrences of patterns of the spectra.

Abstract: A rotation sensor including: a main rotor that integrally rotates with a rotor to be measured; a sub-rotor that rotates in accordance with rotation of the main rotor with a different number of revolutions from that of the main rotor; a first detector detecting rotation of the main rotor; and a second detector detecting rotation of the sub-rotor. The rotation sensor detects an absolute rotation angle of the rotor to be measured from detection signals from the first detector and the second detector. Respective detection signals obtained from the first detector and the second detector are cyclically output in accordance with rotation of each rotor, and the following relationship is satisfied: (Tm?Tc×i)×n=Tm (i and n are positive integers), wherein Tc is a cycle of the detection signal from the first detector, and Tm is a cycle of the detection signal from the second detector.

Abstract: An inductive proximity sensor is disclosed. The proximity sensor includes a housing having at least a first pair of inductive coils disposed within the housing. One of the first pair of inductive coils is opposite in polarity from another one of the first pair of inductive coils. The sensor optionally includes a second set of inductive coils, having opposite polarity.

Abstract: A plurality of layers of flat coils are stacked and connected in series with each other to form a single coil pole, and the coil pole is energized by an A.C. signal. Magnetism-responsive member, provided to be opposed to the coil pole in a non-contact manner, is displaced relative to the coil pole, so that correspondency, to the coil section, of the magnetism-responsive member varies in response to variation in the relative position and thus impedance variation occurs in the coil pole. Position detection signal is provided on the basis of an output signal, responsive to the impedance variation, taken out from the coil pole.

Abstract: A system and method for determining the location of a remote object connected to an induction coil using a magnetic tracking sensor. The system and method include locating a magnetic core asymmetrically disposed within the induction coil located near the remote object, and operably connecting a single DC electrical circuit o ends defining the induction coil. The DC electrical circuit provides a DC current to the induction coil while the induction coil is disposed in an external AC magnetic field. The DC current adjusts the level of saturation of the magnetic core, and hence varies a response signal of the induction coil disposed in the external AC magnetic field to provide magnetic tracking of the induction coil.

Abstract: An inductive position sensor uses three inductors. First and second inductors are separated by a fixed distance with the first inductor's axial core and second inductor's axial core maintained parallel to one another. A third inductor is disposed between the first and second inductors with the third inductor's axial core being maintained parallel to those of the first and second inductors. The combination of the first and second inductors are configured for relative movement with the third inductor's axial core remaining parallel to those of the first and second inductors as distance changes from the third inductor to each of the first inductor and second inductor. In operation, a source supplies an oscillating current to at least one of the three inductors, while another device measures voltage induced in at least one of the three inductors not supplied with the oscillating current.

Abstract: A position sensing assembly includes a bearing element and a helically shaped rotational member used to drive a portion of a sensor assembly, such as a Digital Rotary Magnetic Encoder. Interaction between the bearing element and a helically shaped rotational member minimizes the presence of backlash in the position sensing assembly. Accordingly, as an actuator assembly drives both a control element, such as a flight control surface, and the position sensing assembly, the sensor assembly generates an output signal that accurately reflects the position of the control element.

Abstract: A position sensor device determines a position of a reciprocating object and includes, (a) at least one magnetically encoded region fixed on a reciprocating object, (b) at least one magnetic field detector, and (c) a position determining unit. The magnetic field detector is adapted to detect a signal generated by the magnetically encoded region when the magnetically encoded region reciprocating with the reciprocating object passes a surrounding area of the magnetically encoded region. The position determining unit is adapted to determine a position of a reciprocating object based on the detected magnetic signal.

Abstract: A method and apparatus for detecting the presence of magnetic beads is disclosed. By providing both a static magnetic field and a magnetic field that alternates in the MHz range, or beyond, the bead can be excited into FMR (ferromagnetic resonance). The appearance of the latter is then detected by a magneto-resistive type of sensor. This approach offers several advantages over prior art methods in which the magnetic moment of the bead is detected directly.

Abstract: A method for restoring navigation failure information in a fluoroscopy-based imaging system is disclosed. The method includes obtaining a plurality of receiver navigation information using a calibration target rigidly attached to a supporting member of the imaging system. The calibration target may include a plurality of receivers providing navigation information and the supporting member may be a C-arm. The method identifies a navigation failure and corresponding to the navigation failure a calibrated receiver navigation information is generated. The calibrated receiver navigation information is generated using a calibration information and a C-arm imaging position obtained during navigation failure. A receiver navigation information corresponding to the navigation failure is estimated using the calibrated receiver navigation information, and a transmitter navigation information.

Abstract: The present invention relates to a method for the detection of a predamping state of an inductive sensor. The sensor has at least one oscillator with a resonant circuit and an oscillation amplifier. According to the method the oscillatory response of the oscillator is analyzed with an operating amplification or gain. According to the invention the method is further developed in that the oscillatory behavior of the oscillator is additionally analyzed for an analysis amplification or gain, which is chosen lower than the operating amplification. The analysis amplification is also chosen in such a way that the oscillatory response of the oscillator reacts sensitively to objects or articles located in close proximity to the sensor. The invention also relates to an inductive sensor with predamping detection.

Abstract: The present invention relates to an inductive proximity switch with an oscillator having a resonant circuit and an amplifier and with an evaluating and control device for evaluating an impedance of the resonant circuit and for outputting a switching signal. According to the invention, the proximity switch is characterized in that a frequency measuring device is provided for measuring the oscillation frequency of the oscillator and for eliminating ambiguities of the evaluation result of the evaluating and control device. The invention also relates to a method for operating an inductive proximity switch.