Abstract: A guarded sense impedance for use in a measurement instrument includes a sense impedance adapted to have a spatially distributed electrical potential and at least one guard structure adapted to have the spatially distributed electrical potential. The guard structure is arranged to provide a spatially distributed guard potential for the sense impedance.

Abstract: Disclosed herein is a plate type capacitive sensor for five-dimensional displacement measurement that is capable of simultaneously measuring five-dimensional movement of an object, which includes the horizontal movement, the vertical movement, and the tilt of the object. The plate type capacitive sensor for five-dimensional displacement measurement comprises a plate located adjacent to an object to be measured, and a ground part, a first guard part, a displacement measuring sensor, and a second guard part, which are stacked on the plate in consecutive order. The plate may be made by machining or made of a printed circuit board (PCB).

Abstract: The invention relates to a flexible, resilient capacitive sensor suitable for large-scale manufacturing. The sensor comprises a dielectric, an electrically conductive detector and trace layer on the first side of the dielectric layer comprising a detector and trace, an electrically conductive reference layer on a second side of the dielectric layer, and a capacitance meter electrically connected to the trace and to the conductive reference layer to detect changes in capacitance upon interaction with detector. The sensor is shielded to reduce the effects of outside interference.

Abstract: Methods and systems are described for efficiently detecting an object. The system includes at least one electrode for measuring a displacement current. The at least one electrode is coupled to a floating ground configuration provided by an op-amp, where the inverting node of the op-amp is coupled to electrode and the non-inverting node is coupled to a signal generator. The system may include a single capacitance sensor for detecting an object. Systems may include a plurality of capacitance sensors in an array configuration for detecting an object.

Abstract: An input device is provided. The input device includes an input electrostatic sensor having an input electrode. A noise detection electrostatic sensor has a noise detection electrode disposed on a periphery of the input electrostatic sensor. A control unit is operable to receive an output signal from the input electrostatic sensor and a noise output signal from the noise detection electrostatic sensor and is operable to compare the output signal with the noise output signal to detect a noise component. The control unit is operable to discriminate the output signal and the noise output signal and is operable to control an input operation based on the output signal.

Abstract: Methods, systems and devices are described for determining a measurable capacitance for proximity detection in a sensor having a plurality of sensing electrodes and at least one guarding electrode. A charge transfer process is executed for at least two executions. The charge transfer process includes applying a pre-determined voltage to at least one of the plurality of sensing electrodes using a first switch, applying a first guard voltage to the at least one guarding electrode using a second switch, sharing charge between the at least one of the plurality of sensing electrodes and a filter capacitance, and applying a second guard voltage different from the first guard voltage to the at least one guarding electrode. A voltage is measured on the filter capacitance for a number of measurements equal to at least one to produce at least one result to determine the measurable capacitance for proximity detection.

Abstract: A measuring apparatus having a probe that faces a surface of a target and is configured to supply AC current to the surface, measuring a voltage drop through a space between the probe and the surface, and obtaining a distance between the probe and the surface in accordance with the measured voltage drop. The apparatus includes a ground member facing, and apart from, the surface and configured to ground the surface by capacitive coupling, and a stage configured to hold either of the target and the probe and to move to define a measurement area on the surface. The ground member is configured so that the ground member faces all areas of the surface with respect to each of a plurality of measurement areas on the surface defined by a position of the stage.

Abstract: At least one exemplary embodiment of the present invention includes a capacitive sensing system, comprising a sensing conductor coupleable to a grounded target by a gap capacitance Cd, said grounded target separated from said sensing conductor by a gap having a width. The capacitive sensing system also comprises a circuit connected to said sensing conductor, an input signal having an input frequency fosc provided to said circuit through an input resistance Rd, an output signal of said circuit having an output voltage varying linearly with the width of the gap when the impedance of the gap capacitance 1/(2?foscCd) approaches or exceeds the input resistance Rd.

Abstract: A measuring apparatus having a probe that faces a surface of a target and is configured to supply AC current to the surface, measuring a voltage drop through a space between the probe and the surface, and obtaining a distance between the probe and the surface in accordance with the measured voltage drop. The apparatus includes a ground member facing, and apart from, the surface and configured to ground the surface by capacitive coupling, and a stage configured to hold either of the target and the probe and to move to define a measurement area on the surface. The ground member is configured so that the ground member faces all areas of the surface, with respect to each of a plurality of measurement areas on the surface defined by a position of the stage.

Abstract: An electrostatic capacitance detection device includes an electrostatic capacitance detection element arranged in M rows and N columns. The electrostatic capacitance detection element includes a signal detection element that retains a charge in proportion to the electrostatic capacitance. The signal detection element includes a capacitance detection electrode and a capacitance detection dielectric layer formed on the capacitance detection electrode. The capacitance detection dielectric layer includes a first semiconductor layer and an insulator disposed between the capacitance detection electrode and the first semiconductor layer. A signal amplification element amplifies a signal corresponding to the retained charge in the signal detection element. The signal amplification element includes a second semiconductor layer different from the first semiconductor layer. A power supply line supplies a power source to the electrostatic capacitance detection element.

Abstract: A device for measuring one or more different properties of soil or a soil-related substance is provided. The device includes a probe that is inserted into the soil or soil-related substance. The probe includes a tip. The tip is electrically insulative and defines apertures. Electrodes are fitted into the apertures. The tip and electrodes are machined together to have a desired shape that is suitable for insertion into a sample. A printed circuit board (“PCB”) is located inside the probe. The electrodes are soldered directly to the PCB in one embodiment. A temperature sensing element is also located in the tip, near the electrodes, and is connected electrically to the PCB.

Abstract: An electrostatic capacitance sensor, includes an electrostatic capacitance detector, an operational amplifier in which a feedback impedance circuit is connected between an output terminal and an inverse input terminal of the operational amplifier, a signal line connected between the inverse input terminal of the operational amplifier and the electrostatic capacitance detector, an alternating-current signal generator connected to a non-inverse input terminal of the operational amplifier, and a shield for shielding at least a portion of the signal line, the shield being connected to the non-inverse input terminal of the operational amplifier and the alternating-current signal generator. The electrostatic capacitance detector includes a detecting electrode and a shield electrode. The detecting electrode includes a detector-detecting electrode for detecting an object to be detected and an electrode introducer-detecting electrode for introducing an electrode to the detector-detecting electrode.

Abstract: A membrane probing assembly includes a probe card with conductors supported thereon, wherein the conductors include at least a signal conductor located between a pair of spaced apart guard conductors. A membrane assembly includes a membrane with contacts thereon, and supporting at least a signal conductor located between a pair of spaced apart guard conductors. The guard conductors of the probe card are electrically interconnected proximate the interconnection between the probe card and the membrane assembly. The guard conductors of the membrane assembly are electrically interconnected proximate the interconnection between the probe card and the membrane assembly.

Abstract: One embodiment of the present invention comprises a sensor with a face having several tracks spaced apart from one another. One of these tracks has a first electrode and a second electrode separated by an electrically nonconductive gap. Also included is a detection device extending across the tracks to receive signals by capacitive coupling. Sensor circuitry electrically coupled to the tracks and the detection device is structured to generate a first number of bits from a sequential signal pattern applied to the tracks in accordance with an established sequence. The circuitry is also structured to generate a second number of bits as a function of a first signal and a second signal. The first bits and second bits represent a position of the detection device along the tracks with the first bits being more numerically significant than the second bits.

Abstract: An electrical capacitance proximity sensor for detecting a nearby object takes a normal operation mode for detecting the nearby object approaching and a self-diagnostic mode for detecting a correct connection between a sensor section and a detecting circuit section. The detecting circuit section is provided with a buffer controller which supplies a second oscillation signal having the same phase and voltage as a first oscillation signal applied to a guard electrode in the normal operation mode, and stops supplying the second oscillation signal in the self-diagnostic mode. A control circuit determines whether the sensor section is correctly connected to the detecting circuit section base on the change in the detecting signal in the normal operation mode and the self-diagnostic mode.

Abstract: A capacitive sensor includes: a first sensing electrode connected to a first reference capacitor in which is stored reference electric charge; a second sensing electrode connected to a second reference capacitor in which is stored reference electric charge; and a shield electrode to which is applied electric potential equal to that of the first sensing electrode and the second sensing electrode. The first sensing electrode positions adjacent to a detecting surface of the capacitive sensor, and the second sensing electrode positions opposite to the detecting surface in such a manner that the first and second sensing electrodes are spaced apart and facing to each other. The shield electrode is configured to partly expose the first and second sensing electrodes on the side of the detecting surface, and the shield electrode extends toward the detecting surface beyond the first sensing electrode.

Abstract: A device for sensing an obstacle in said opening range of an automotive closure element movable between an open position and and closed position, more particularly an electrically powered door window (20) or sunroof is provided with a weatherseal (30) sealing the window pane (20). The weatherseal (30) is made of an elastomeric material and secured to a frame (12) of the motor vehicle (10). The device comprises in addition a sensor for sensing an obstacle in the opening range of the closure element (20), the sensor comprising at least one electrical conductor (40) generating an electrical field (F) in the opening range of the closure element (20). The device achieves by simple ways and means an engineered orientation of the electrical field such that any interference by the closure element (20) to the capacitive change in the electrical field (F) is precluded by reason of conductive means (50) comprising a conductive surface (51) made of an electrically conductive material.

Abstract: A non-contact capacitive sensor probe including a metallic sensor having a first surface opposite a dielectric medium to be sensed; a plurality of active metallic shields adjacent to the metallic sensor, each of the active metallic shields having a pattern of grooves inhibiting eddy currents on a surface of the shield, wherein the pattern on one shield does not overlap with the pattern on a second shield, and a passive metallic shield adjacent the active metallic shields, such that active metallic shields are sandwiched between the metallic sensor and the passive metallic shield.

Abstract: A planar fingerprint pattern detecting array includes a large number of individual skin-distance sensing cells that are arranged in a row/column configuration. Each sensing cell includes an amplifier having an ungrounded input node and an ungrounded output node. Output-to-input negative feedback that is sensitive to the fingerprint pattern is provided for each amplifier by way of (1) a first capacitor plate that is placed vertically under the upper surface of a dielectric layer and is connected to the ungrounded amplifier input node, (2) a second capacitor plate that is placed vertically under the upper surface of the dielectric layer in close horizontal spatial relation to the first capacitor plate and is connected to the ungrounded output node, and (3) an ungrounded fingertip whose fingerprint pattern is to be detected, which ungrounded fingertip is placed on the upper surface of the dielectric layer in close vertical spatial relation with the first and second capacitor plates.

Abstract: A membrane probing assembly includes a probe card with conductors supported thereon, wherein the conductors include at least a signal conductor located between a pair of spaced apart guard conductors. A membrane assembly includes a membrane with contacts thereon, and supporting at least a signal conductor located between a pair of spaced apart guard conductors. The guard conductors of the probe card are electrically interconnected proximate the interconnection between the probe card and the membrane assembly. The guard conductors of the membrane assembly are electrically interconnected proximate the interconnection between the probe card and the membrane assembly.

Abstract: A detection system for detecting a dangerous condition for an operator using a power tool of the type which has an exposed blade relative to a work surface and a protection system for minimizing, if not eliminating the possibility of a user being injured by contacting the blade. In one preferred embodiment of the present invention, a proximity detection system is capable of detecting the presence of a user near the blade of a table saw and a protection system that can either retract the blade below the work surface of the table saw or terminate the drive torque to the blade which can result in rapid stopping of the saw blade by a work piece that is being cut.

Abstract: A voltage divider (102) for high voltage and other applications uses a high voltage impedance element (104) and a low voltage impedance element (106) to isolate a sample node (110) from which to measure current, voltage, frequency response and other characteristics. The high voltage impedance element (104) includes a resistive network for reducing high voltages, for instance power line voltages of 20 kV or more, down to instrument levels to take measurements on insulation or other materials. The high voltage impedance element (104) is surrounded by one or more capacitive guard elements (118) which shunt stray capacitive currents to ground, improving frequency response and other characteristics. The voltage divider (102) be connected to a current receiver (112) for purposes of instrumentation.

Abstract: The invention relates to a locator, in particular a handheld locator for detecting inclusions in walls, ceilings and/or floors, having a capacitive sensor device disposed in a housing, having means for generating a detection sensor of the at least one capacitive sensor device, having a control and evaluation unit, communicating with the sensor device, for ascertaining measurement values from the detection sensor, and having an output unit for reproducing measurement values of the capacitive sensor device. According to the invention, it is proposed that a measuring capacitor (16) of the capacitive sensor device (10) has a first electrode (21), which includes one face of the housing (14) of the sensor device (10).

Abstract: There is described a portable device (1) including in particular a case (2) closed by a glass (3) and containing device for detecting the presence of water (22) in contact with an external region of the assembly formed by the case and the glass. In a preferred embodiment, the device for detecting the presence of water include a plurality of capacitive sensors (20) arranged in a peripheral region of the device (1) so as to undergo a variation in their respective capacitances when the latter is immersed in water. Thus, a quantity characteristic of the capacitance value of each sensor (20) is periodically measured and stored. After each measurement, the new value obtained is compared to the preceding one to detect any variation in the corresponding capacitance. When a part of the capacitive sensors (20) simultaneously see their respective capacitances vary considerably between two measurements, detection of the presence of water is validated.

Abstract: An electric field proximity detector capable of detecting partially conductive or conductive objects regardless of their impedance to circuit ground. The detector has a sensor with a transmitting electrode, a receiving electrode, and at least one circuit ground electrode preferably arranged in a bulls-eye configuration with the ground electrode between the transmitter and receiver electrodes. With appropriate sizing, upon the approach of an object, a signal received by the receiving electrode decreases, at least until the object is within a threshold distance of the sensor. The size and positioning of the ground electrode further reduces the effects of stray capacitance.

Abstract: An electrostatic capacitance sensor, includes an electrostatic capacitance detector, an operational amplifier in which a feedback impedance circuit is connected between an output terminal and an inverse input terminal of the operational amplifier, a signal line connected between the inverse input terminal of the operational amplifier and the electrostatic capacitance detector, an alternating-current signal generator connected to a non-inverse input terminal of the operational amplifier, and a shield for shielding at least a portion of the signal line, the shield being connected to the non-inverse input terminal of the operational amplifier and the alternating-current signal generator. The electrostatic capacitance detector includes a detecting electrode and a shield electrode. The detecting electrode includes a detector-detecting electrode for detecting an object to be detected and an electrode introducer-detecting electrode for introducing an electrode to the detector-detecting electrode.

Abstract: This disclosure describes a Soil Penetrating Electrode with Conical Taper for use with instrumentation for measurement of the electrical properties of soil in situ. The Electrode shape and configuration solves problems of stable and reliable contact with the soil, repeatable contact area, and ease of use by the operator.

Abstract: A probe for connecting a device under test to a measurement device that corrects for dc errors and noise generated by the current flowing through the ground shield of a transmission line used by the probe. The probe identifies a voltage drop in the ground preferably using an additional line between the device under test and the measurement device. The signal provided to the measurement device is corrected based on the identified voltage drop.

Abstract: A sensor includes a substrate consisting essentially of a non-conductive material, a first electrode, and a second electrode disposed on a first surface of the substrate, wherein the first electrode includes a first major portion traversing a length of the substrate and a finger extending from the major portion, wherein the second electrode includes a second major portion traversing the length of the substrate and a finger extending from the second major portion, wherein the first electrode finger extends toward the second electrode major portion and the second electrode finger extends toward the first electrode major portion and is substantially parallel to the first finger, and a third electrode connected to a ground, wherein the third electrode is interposed between and about the first and second electrodes.

Abstract: In one embodiment, a radio frequency (RF) configuration in a plasma processing system includes an RF electrode driven by an RF signal source and a non-RF electrode coupled to an electronic module. A filter coupled to the non-RF electrode is configured to provide maximum attenuation at or near an RF signal frequency, while allowing signals associated with the electronic module to pass. The filter may be placed as close to the non-RF electrode as possible. The filter may be, for example, a band stop filter such as a parallel resonant circuit having a resonant frequency at or near an RF signal frequency.

Abstract: A non-contact capacitive displacement measurement gage that provides high accuracy displacement measurements of well-connected targets and poorly-connected targets. The capacitive displacement measurement gage includes a capacitive probe, first and second amplifiers, and a signal generator. The capacitive probe includes a sensor electrode, a guard electrode, and a compensating electrode. The signal generator provides a predetermined voltage signal directly to the sensor electrode, to the guard electrode through the first amplifier having unity gain, and to the compensating electrode through the second amplifier having a predetermined transfer function. The second amplifier assures that substantially zero current is driven into the target element by the probe during gage operation, thereby allowing highly accurate displacement measurements of target elements having unknown or poorly controlled impedance.

Abstract: Both a sensor portion and a signal processing portion are provided on a glass board. The sensor portion is formed by subjecting a conductive layer to the patterning process. A gold coupling layer is provided on the conductive layer and the signal processing portion is formed by the flip chip method on the coupling layer. The sensor portion and the signal processing portion may be formed on the major surface and the rear surface of the glass board and these portions may be coupled by through holes. Since the signal processing portion as well as the sensor portion is formed on the glass board, the wiring distance can be made shorter and the entire size of the sensor can be miniaturized.

Abstract: Within a capacitive fingerprint detection device, finger detection is provided by a capacitive grid overlying the fingerprint sensor electrodes to measure the absolute capacitance of the finger placed on the sensor surface. The capacitive measurement is converted to a representative frequency, which is then compared to a reference frequency or frequency range to determine whether the measured capacitance matches the expected bio-characteristics of living skin tissue. The finger detection thus provides anti-spoofing protection for the fingerprint detection device.

Abstract: This invention is directed to a method of making a capacitive distance sensor that includes one or more sensor cells each with first and second capacitor plates. The method includes determining an expected range of sizes of objects the sensor will be used to detect and determining a total perimeter value for each of a plurality of capacitor patterns. Each capacitor pattern includes a different arrangement of the first and second capacitor plates and the total perimeter value is the sum of the perimeter values for the first and second capacitor plates. The method selects one of the capacitor patterns based on the expected size of the object and on the total perimeter values determined for the capacitor patterns. The selecting step includes selecting whichever one of the capacitor patterns has the largest total perimeter value if the object is smaller than each of the one or more sensor cells.

Abstract: A capacitance measuring circuit having a sensor electrode and a reference electrode that are spaced apart so that a material can be positioned between the two electrodes. A first polarity and a second polarity voltage source are used to charge the sensor electrode and a switch controller controls the charging and discharging of a capacitor by the sensor electrode. The charge on the capacitor after being charged and at least partially discharged by the sensor electrode represents the capacitance between the sensor electrode and the reference electrode. The charge on the capacitor is used to measure the position of the material relative to the sensor and reference electrode. The measuring circuit also has a system parasitic controller to measure and adjust for system parasitic capacitance in the measuring circuit.

Abstract: A dielectrometer with a sensor face that carries an excitation electrode driven with a varying voltage. At least two sensing electrodes and a guard electrode are also carried by the sensor face. The sensing electrodes are adapted for single or multiple penetration depth measurements into a test material. The guard electrode surrounds the sensing electrodes and is at about the same voltage as the sensing electrodes.

Abstract: In a measuring circuit for a capacitive sensor for distance measurement and/or space monitoring comprising sensor wire and shielding electrode, a sine signal is applied to the shielding electrode. The sensor wire is connected, via a shielded cable, with one input of an input amplifier which serves as current-voltage converter and whose supply voltage is likewise influenced by the sine signal. The output of the input amplifier is connected with one input of a phase-dependent rectifier arrangement, the sine signal is applied to the other input of the phase-dependent rectifier arrangement, and its output is connected to an analog-to-digital converter.

Abstract: The capacitive angular displacement transducer includes a first stator (2) comprising a plurality of electrically conductive; circular ring-shaped electrodes (51) which are electrically isolated from each other and have a predetermined sector angle, with a second stator (4) arranged parallel to the first stator comprising a receiving electrode (6), and with a rotor (3) mounted on a rotatable shaft (7) comprising at least one rotor blade (8a, 8b) in the form of circle sectors and located perpendicular to the shaft and the rotor blade being located parallel to and between the first and the second stators. The sum of the central angles of all transmitting electrodes is less than 2&pgr; (360°), preferably ranging from &pgr;/12 (30°) to 5&pgr;/6 (300°), and the central angle of each rotor blade is essentially equal to the sum of the central angles of n adjacent or neighboring transmitting electrodes.

Abstract: An exemplary embodiment of the invention is a sensing circuit for use with a proximity sensor having a first electrode and a second electrode and a capacitance between the first electrode and the second electrode. The sensing circuit includes a signal generator for generating an alternating signal. The signal generator is for connection to the first electrode of the sensor. A synchronous detector has a first input for connection to the second electrode of the sensor. A phase shifter is coupled to the signal generator and generates a phase shifted signal in response to the alternating signal. The phase shifted signal is provided to a second input of the synchronous detector. The synchronous detector detects a change in the capacitance between the first electrode and the second electrode in response to a signal from the second electrode and the phase shifted signal.

Abstract: A distance sensor has a capacitive element in turn having a first capacitor plate which is positioned facing a second capacitor plate whose distance is to be measured. In the case of fingerprinting, the second capacitor plate is defined directly by the skin surface of the finger being printed. The sensor comprises an inverting amplifier, between the input and output of which the capacitive element is connected to form a negative feedback branch. By supplying an electric charge step to the input of the inverting amplifier, a voltage step directly proportional to the distance being measured is obtained at the output.

Abstract: A capacitive displacement sensor for measuring thin targets is presented. The plate of the measurement probe is designed to take into account the thin target shape and to provide accurate measurements of the thin target by reducing lateral movement sensitivity of the plate. The probe may also include a guard to reduce capacitive coupling of the plate with other structures which would affect the accuracy of the measurement.

Abstract: An apparatus for measuring ignition charge signals produced by coils of coil-on-plug devices of an internal combustion engine. A signal detector comprises an insulating substrate having a first conductive planar layer on a first side and a second conductive planar layer on a second side. The first layer is coupled to a signal wire and the second layer is coupled to a ground wire. When the signal detector is held in close proximity to the coil of the coil-on-plug, ignition signals generated by the coil and passing to the plug are detected. The detected signals may be coupled to a signal analyzer for display and analysis. The amplitude of the signal that is output by the signal detector may be adjusted to different coils having different output signal strengths by modifying the ratio of the surface areas of the first layer and the second layer.

Abstract: A method is disclosed for processing, optimization, calibration, and display of measured dielectrometry signals. A property estimator is coupled by way of instrumentation to an electrode structure and translates sensed electromagnetic responses into estimates of one or more preselected properties or dimensions of the material, such as dielectric permittivity and ohmic conductivity, layer thickness, or other physical properties that affect dielectric properties, or presence of other lossy dielectric or metallic objects. A dielectrometry sensor is disclosed which can be connected in various ways to have different effective penetration depths of electric fields but with all configurations having the same air-gap, fluid gap, or shim lift-off height, thereby greatly improving the performance of the property estimators by decreasing the number of unknowns.

Abstract: A displacement/angular position sensor including a potentiometer path (20), which is arranged on a carrier (10) and to which an alternating voltage can be applied, a collector path (30) arranged on the carrier (10), a first probe (70) guided for displacement above the potentiometer path (20), and a second probe (80) electrically coupled with the latter and guided for displacement above the collector path. Screening surfaces (11, 12, 13, 14), connected to frame potential, are provided that surround the potentiometer path (20) and the collector path (30) and the probes guided above them so that both the potentiometer path (20) with the first probe (70) associated to it and the collector path (30) with the second probe (80) associated to it are each arranged in a spatially separate, screened space (22,32).

Abstract: A microelectrical resistance tomography system comprising one or more sensors, each sensor including a wafer substrate of electrically insulating material having an aperture bounding a fluid flow path through a tube and a plurality of sensor electrodes on the substrate disposed circumferentially around the aperture so as to contact the fluid.

Abstract: A film position detection apparatus and a method for precisely detecting a film position are provided. An image film projection apparatus is also provided for correcting deflections of images through precisely detecting a film position and thereby projecting images recorded on the film in a good condition. A film position detection means has a ground electrode attached to a movable picture gate; detection electrodes placed in a fixed picture gate; and auxiliary electrodes placed around the detection electrodes. The auxiliary electrodes suppress erroneous variations in electrostatic capacitance generated between the ground electrode and the detection electrodes. As a result, accuracy in film position detection by the detection electrodes is improved for achieving precise detection.

Abstract: A method and apparatus for measuring at least one parameter including mass flow rate or moisture content of material moved by a conveyor are disclosed herein. The method includes the steps of applying an electric field to the material using a non-intrusive sensor assembly, generating signals related to the dielectric value of the material, and processing the signals to determine the parameter. The apparatus includes a capaciflector sensor assembly located along a surface of the conveyor to generate an electric field applied to the material and a processing circuit to determine the parameter based upon the signals output from the sensor assembly. The sensor assembly includes a first conductor spaced between a stationary member of the conveyor and the material, and a second conductor spaced between the first conductor and the stationary member to act as a shield for reducing parasitic capacitance between the first conductor and a reference plane.

Abstract: The composition of an electrically conductive mixture, such as a mixture of gasoline and alcohol, is measured using a single measurement cell having a first electrode and a second electrode with a measurement space therebetween for receiving a specimen of the mixture. With a specimen of the mixture in the measurement space, the first electrode is alternatively connected to a reference discharge voltage, preferably ground, and to an applied voltage through a resistor. A first operational state encompasses the period when the first electrode is connected to the reference discharge voltage and a second operational state encompasses the period when the first electrode is connected to the applied voltage through the resistor. A first operational state peak voltage is measured during the first operational state, and a second operational state peak voltage is measured during the second operational state.

Abstract: This invention relates to a fluid screening device, comprising: an impedance sensor including a cavity for holding a fluid to be screened, an impedance of the impedance sensor being affected by conditions of the fluid; an impedance measuring circuit for measuring the impedance of the impedance sensor with respect to at least one frequency; a processor for processing impedance data taken by the impedance measuring circuit for purposes of determining a condition of the fluid; and a connector which operatively couples the impedance sensor to the impedance measuring circuit, the connector allowing the impedance sensor to be selectively detached from the impedance measuring circuit.

Abstract: A capacitive level sensor for sensing level of a in a vessel includes a sensor coupled to the vessel having a shield and an inner sensing rod. An oscillator provides an RF signal to the shield and the sensing rod. Comparison circuitry couples to the sensing rod provides a wet/dry output in response to capacitance between the inner sensing rod and the vessel, the capacitance related to the level of the liquid in the vessel.