Including A Tuned Or Resonant Circuit Patents (Class 324/675)
  • Patent number: 9778017
    Abstract: Provided is an apparatus capable of distinguishing a kind of a powder deposited on an inner surface of a pipe, and more precisely measuring a thickness of the powder deposited on the inner surface of the pipe. The apparatus for measuring a thickness of a powder deposited on an inner surface of a pipe, includes a pair of the first electrodes disposed adjacent to one portion of the inner surface of the pipe and used to measure a first capacitance and thus to distinguish a kind of the powder, and a pair of second electrodes disposed in the pipe to be spaced from each other and to be symmetrical with respect to a center portion of the pipe and used to measure a second and a third capacitance.
    Type: Grant
    Filed: December 1, 2014
    Date of Patent: October 3, 2017
    Inventor: Kwang-Youn Kim
  • Publication number: 20150107356
    Abstract: Apparatus for determining and/or monitoring at least one limit value of a process variable of a medium in a container, comprising at least one sensor unit for registering a measured value dependent on the process variable and at least one electronics unit for producing a measurement signal dependent on the process variable. The invention is distinguished by features including that the apparatus is embodied to draw energy via a voltage output and a digital input of a recorder apparatus or a process control system.
    Type: Application
    Filed: November 22, 2012
    Publication date: April 23, 2015
    Applicant: Endress + Hauser GmbH + Co. KG
    Inventors: Christoph Schleith, Michael Dotsch
  • Patent number: 8952708
    Abstract: Processes and apparatuses are provided for contactless measuring or monitoring in-situ and in real time composition or other electromagnetic impedance correlated properties of liquid or gaseous substances or bulk materials. One or more apparatus may include a resonance type impedance sensor having at least two coils, at least one coil of the at least two coils being at least one excitation coil connectable to at least one alternating current source with frequency sweep, at least one other coil of the at least two coils being at least one sensing coil connectable to at least one data processing system. The one or more methods may include calculating changes in amplitude and resonant frequency induced by electromagnetic interaction between said sensor and object to determine impedance of said object under test; and matching said impedance with predetermined calibration data to determine said chemical or physical properties of said object under test.
    Type: Grant
    Filed: November 30, 2012
    Date of Patent: February 10, 2015
    Assignee: NeoVision LLC
    Inventor: Yury Nikolenko
  • Patent number: 8610440
    Abstract: A method for in situ monitoring of a membrane of a membrane separation system comprises measuring a complex impedance of the membrane at a plurality of frequencies to provide an indication of the electrical conduction and electrical polarization properties of the membrane. The membrane based separation system for removing or reducing the concentration of materials carried in a fluid including a separation membrane has a first pair of electrodes separated by the membrane and arranged for measurement of the complex impedance of the membrane at a plurality of frequencies to provide the indication of the membrane properties. There may also be a second pair of electrodes separated by the membrane for injecting the stimulus current such that the injecting and monitoring functions are separated.
    Type: Grant
    Filed: September 11, 2008
    Date of Patent: December 17, 2013
    Inventors: Hans Gerard Leonard Coster, Terry Calvin Chilcott
  • Patent number: 8558558
    Abstract: The invention relates to a method and a monitoring system for automatically actuated, in particular power-driven closing covers, for example boot lids of motor vehicles. The invention also relates to a method and a detection system for detecting the presence of objects per se. The aim of the invention is to provide solutions for the implementation of a reliable safety system.
    Type: Grant
    Filed: January 12, 2007
    Date of Patent: October 15, 2013
    Assignee: Ident Technology AG
    Inventor: Wolfgang Richter
  • Publication number: 20130176038
    Abstract: Permittivity sensor and method comprising: an oscillator (L,40) having operating characteristics (F,V); permittivity sensing element (30) coupled to the oscillator and arranged to alter the operating characteristics of the oscillator in response to changes in permittivity presented to the permittivity sensing element; a reference element (110) switchably (220) coupled to both the oscillator and the permittivity sensing element and arranged to alter the operating characteristics of the oscillator. Method of measuring the composition of a fuel comprising the steps of: measuring a real permittivity of the fuel; measuring an imaginary permittivity of the fuel; determining a proportion of biodiesel in the fuel based on the measured real permittivity. Determining a proportion of unrefined oil in the fuel based on the measured imaginary permittivity.
    Type: Application
    Filed: July 13, 2011
    Publication date: July 11, 2013
    Applicant: Oxford RFSensors Ltd
    Inventor: Peter Wherritt
  • Patent number: 8456177
    Abstract: An occupant detection system that includes an electrode arranged proximate to an expected location of an occupant for generating an electric field between the electrode and the occupant proximate thereto. An electrical network coupled to the electrode forms a resonant circuit that includes the occupant as part of the resonant circuit. A controller coupled to the resonant circuit is configured to determine a resonant frequency of the resonant circuit indicative of an occupant presence, and a network signal magnitude at the resonant frequency indicative of a humidity value proximate to the electrode. 7. A method for detecting a vehicle applies an excitation signal to the resonant circuit, determine a resonant frequency of the resonant circuit and determines a humidity value based on a network signal magnitude at the resonant frequency.
    Type: Grant
    Filed: August 7, 2012
    Date of Patent: June 4, 2013
    Assignee: Delphi Technologies, Inc.
    Inventors: Dennis P. Griffin, Mark C. Hansen
  • Patent number: 8432171
    Abstract: An analyte concentration, in a sample fluid, is determined by differential measurement. Two or more capacitive field effect sensors have an identical basic structure and are arranged in a shared measuring cell. One of the sensors forms a measuring sensor with an active transductor layer. Another sensor forms a reference sensor without an active transductor layer. The sensors are contacted with the sample fluid and the sensors, have an associated reference electrode, or have a shared reference electrode. A bias voltage composed of an electric DC voltage and a superimposed AC voltage is applied between each sensor and associated reference electrode(s) Capacitance changes due to the analyte are eliminated by controlling the bias voltage applied to the measuring sensor in a closed control loop. A measuring signal is obtained by calculating a difference between voltage values representative of DC voltage potentials applied to the measuring sensor and reference sensor, respectively.
    Type: Grant
    Filed: April 28, 2010
    Date of Patent: April 30, 2013
    Assignee: Buerkert Werke GmbH
    Inventors: Thomas Coppe, Jean-Luc Henry, Michael Schoening
  • Patent number: 8217665
    Abstract: A patch-clamp system employs a high-frequency characterization of cell wall membranes. Changes in the frequency response of a tank circuit incorporating the cell wall membrane impedance provides highly sensitive and highly time-resolved measurements of ion channel activity.
    Type: Grant
    Filed: November 25, 2008
    Date of Patent: July 10, 2012
    Assignee: Wisconsin Alumni Research Foundation
    Inventors: Robert H. Blick, Hua Qin
  • Publication number: 20120166095
    Abstract: Methods and sensors for selective fluid sensing are provided. A sensor includes a resonant inductor-capacitor-resistor (LCR) circuit and a sensing material disposed over the LCR circuit. The sensing material includes a coordination compound of a ligand and a metal nanoparticle. The coordination compound has the formula: (X)n-M, where X includes an alkylamine group having the formula (R—NH2), an alkylphosphine having the formula (R3—P), an alkylphosphine oxide having the formula (R3P?O), an alkyldithiocarbamate having the formula (R2NCS2), an alkylxanthate having the formula (ROCS2), or any combination thereof, R includes an alkyl group, n is 1, 2, or 3, and M includes the metal nanoparticle of gold, silver, platinum, palladium, alloys thereof, highly conductive metal nanoparticles, or any combination thereof. The sensing material is configured to allow selective detection of at least six different analyte fluids from an analyzed fluid mixture.
    Type: Application
    Filed: December 23, 2010
    Publication date: June 28, 2012
    Applicant: General Electric Company
    Inventors: Radislav Alexandrovich Potyrailo, Cheryl Margaret Surman, Binil Kandapallil
  • Patent number: 8085247
    Abstract: An oscillating signal of relatively precise frequency is generated by tuning an oscillator using an external stable oscillating source as a reference. Calibration logic is included to compare a signal from the local oscillator to the reference signal and vary the local signal to a desired frequency. In one embodiment, a binary search algorithm is used to tune the local oscillator. The local oscillating signal can be sent to one or more circuits including at least one sensor of a touch sensitive panel for detecting touch events.
    Type: Grant
    Filed: January 3, 2007
    Date of Patent: December 27, 2011
    Assignee: Apple Inc.
    Inventor: Thomas James Wilson
  • Publication number: 20110012621
    Abstract: The invention relates to a method and a monitoring system for automatically actuated, in particular power-driven closing covers, for example boot lids of motor vehicles. The invention also relates to a method and a detection system for detecting the presence of objects per se. The aim of the invention is to provide solutions for the implementation of a reliable safety system.
    Type: Application
    Filed: January 12, 2007
    Publication date: January 20, 2011
    Inventor: Wolfgang Richter
  • Publication number: 20100268479
    Abstract: A system for selectively determining at least two analytes, comprising at least one resonant sensor circuit comprising a sensing material that predictably affects the resonant complex impedance response of a sensor electrode, wherein the sensing material having at least two material properties that change upon exposure to two or more analytes; and a processor that generates a multivariate sensor response pattern that is based at least in part on a change in the two material properties of the sensing material and a sensing device and methods adapted to detect an analyte using the same sensor system.
    Type: Application
    Filed: April 15, 2009
    Publication date: October 21, 2010
    Applicant: GENERAL ELECTRIC COMPANY
    Inventors: Radislav Alexandrovich Potyrailo, James Anthony Cella, Cheryl Margaret Surman, Kelly Scott Chichak, Steven Go
  • Publication number: 20100127716
    Abstract: A patch-clamp system employs a high-frequency characterization of cell wall membranes. Changes in the frequency response of a tank circuit incorporating the cell wall membrane impedance provides highly sensitive and highly time-resolved measurements of ion channel activity.
    Type: Application
    Filed: November 25, 2008
    Publication date: May 27, 2010
    Inventors: Robert H. Blick, Hua Qin
  • Patent number: 7701228
    Abstract: According to some embodiments, motor-tuned nuclear magnetic resonance (NMR) probes may be tuned manually without overcoming the tuning motor holding force. An NMR probe includes a switchable manual-mode/motor-driven mode capacitance-adjustment assembly for adjusting the capacitance of a variable capacitor connected to an NMR RF coil. The capacitance-adjustment assembly includes a tuning shaft coupled to the variable capacitor through a gear assembly, and a mode-switching coupler coupled to the tuning shaft. The mode-switching coupler includes a first terminal coupled to a piezoelectric motor, and a second terminal coupled to the tuning shaft. In the manual mode, a user pushes up the tuning shaft, decoupling the two terminals of the mode-switching coupler and thus decoupling the motor from the tuning shaft. The user then manually rotates the tuning shaft. In the motor-driven mode, a spring tensioner presses the two terminals of the mode-switching coupler together, coupling the motor to the tuning shaft.
    Type: Grant
    Filed: March 11, 2008
    Date of Patent: April 20, 2010
    Assignee: Varian, Inc.
    Inventor: Jim Finnigan
  • Patent number: 7687803
    Abstract: A semiconductor device includes a semiconductor chip and a wiring substrate. The wiring substrate is configured to be electrically connected to the semiconductor chip, and have a plurality of terminals arranged on an surface opposite to a surface on which the semiconductor chip is mounted. The plurality of terminals includes a plurality of first terminals configured to be arranged closely to each other, and a plurality of second terminals configured to be arranged so as to surround the plurality of first terminals. The plurality of second terminals is provided such that terminals of the semiconductor chip are connected to outer terminals through the plurality of second terminals. Each of the plurality of first terminals is not provided with a metal ball, while each of the plurality of second terminals is provided with a metal ball.
    Type: Grant
    Filed: June 8, 2006
    Date of Patent: March 30, 2010
    Assignee: NEC Electronics Corporation
    Inventors: Naohiro Takagi, Yasuhiro Suzuki, Kazuaki Satou
  • Patent number: 7605593
    Abstract: Inconsistencies in a resin-based part are detected using a capacitive coupling probe having a tuned circuit and an impedance matching element. An alternating electric field produced by the probe penetrates the part. Inconsistencies in the resin part result in changes in the resonance of the circuit which are detected by a network analyzer.
    Type: Grant
    Filed: January 16, 2007
    Date of Patent: October 20, 2009
    Assignee: The Boeing Company
    Inventor: Steven K. Brady
  • Publication number: 20090001997
    Abstract: Systems and methods for determining a total acid number associated with biodiesel in a mixture of biodiesel and petrodiesel are provided. The method includes receiving an oscillatory signal at an inductance-capacitance-resistance circuit. The circuit has a sensing element fluidly communicating with the mixture of biodiesel and petrodiese. The method further includes generating a resonant current at a resonant frequency utilizing the circuit in response to the oscillatory signal. The method further includes determining a dielectric constant value indicating a dielectric constant associated with the biodiesel in the mixture based on the resonant frequency of the resonant current, utilizing a microprocessor. The method further includes determining a concentration value indicating a concentration of the biodiesel in the mixture based on an amplitude of the resonant current and the dielectric constant value, utilizing the microprocessor.
    Type: Application
    Filed: June 29, 2007
    Publication date: January 1, 2009
    Inventors: Yingjie Lin, Su-Chee S. Wang, Ming-Cheng Wu
  • Publication number: 20080169828
    Abstract: Inconsistencies in a resin-based part are detected using a capacitive coupling probe having a tuned circuit and an impedance matching element. An alternating electric field produced by the probe penetrates the part. Inconsistencies in the resin part result in changes in the resonance of the circuit which are detected by a network analyzer.
    Type: Application
    Filed: January 16, 2007
    Publication date: July 17, 2008
    Inventor: Steven K. Brady
  • Patent number: 6943567
    Abstract: When using solenoid coils in an explosion-hazard environment, in order that no sparks are produced in the event of a discontinuity in an electrical line leading to the solenoid coil, two or more identical zener diodes are connected in parallel with one another and to the solenoid coil. In order to verify the operability of all the zener diodes which are connected in parallel with one another and to the solenoid coil, the electrical values of the zener diodes and of the solenoid coil are measured before assembly. The total capacitance of the circuit arrangement is measured after assembly. The capacitance of the solenoid coil is subtracted from the total capacitance, and the remaining value is divided by the number of parallel-connected zener diodes. The result is compared with the capacitance of a single zener diode, with the magnitude of the difference between these values being used as a criterion for the operability of the zener diodes.
    Type: Grant
    Filed: November 16, 2002
    Date of Patent: September 13, 2005
    Assignee: Bosch Rexroth AG
    Inventors: Karlheinz Panzer, Peter Hartmann
  • Patent number: 6856143
    Abstract: A method for measuring a capacitance of a device under test is provided that includes selectively charging and discharging a first conductor with a first set of p and n element-pairs in response to a voltage potential applied to the first set of p and n element-pairs. The method further includes selectively charging and discharging a second conductor with a second set of p and n element-pairs in response to a voltage potential applied to the second set of p and n element-pairs. Currents are measured at drains associated with the first set of p element-pairs as the first and second conductors charge and discharge such that a capacitance associated with the first conductor may be determined that is based on the drain currents.
    Type: Grant
    Filed: June 14, 2002
    Date of Patent: February 15, 2005
    Assignee: Texas Instruments Incorporated
    Inventors: Michael J. McNutt, Robin C. Sarma, Yu-Sang Lin
  • Patent number: 6842009
    Abstract: A sensing system for a target includes a member with an embedded charge, at least one input electrode, at least one output electrode, at least one common electrode, one or more probes, an input system, and an output monitoring system. The input and output electrodes are spaced from and on substantially opposing sides of the member from the common electrode. At least one of the member and the input and output electrodes is movable with respect to the other. The probes which engage with the target hazardous substance are connected to the at least one of the member and the input and output electrodes which is movable with respect to the other. The input system is coupled between the at least one input electrode and the at least one output electrode and provides an input signal. The output monitoring system is coupled between the at least one output electrode and the at least one common electrode and detects a change in an output signal when the target engages with the movable member or electrode.
    Type: Grant
    Filed: June 3, 2003
    Date of Patent: January 11, 2005
    Assignee: Nth Tech Corporation
    Inventor: Michael D. Potter
  • Patent number: 6559656
    Abstract: Measurement of the permittivity of thin films is facilitated through the use of a short cylindrical metal cavity containing parallel plates between which a specimen to be measured is placed. The use of such parallel plates contained within such a cavity is particularly advantageous when swept frequency measurement methods utilizing frequency ranges from 0 to 20 GHz are employed. A test fixture which is preferred for use in providing such a cavity is disclosed as are methods of using the test fixture.
    Type: Grant
    Filed: December 28, 2000
    Date of Patent: May 6, 2003
    Assignee: Honeywell Advanced Circuits, Inc.
    Inventor: Yutaka Doi
  • Patent number: 6496020
    Abstract: A method for analyzing a dielectric medium comprises the step of measuring, at one or more frequencies, the capacitance between a pair of electrodes immersed in the dielectric medium. The proportion of the or each capacitance measurement due to electrode polarization capacitance and/or to the residual capacitance of the dielectric medium is then determined using capacitance measurements made between the electrodes at a first frequency and at a second frequency, the ratio of the respective polarization capacitances at these two frequencies being predetermined. An apparatus for performing the method is also disclosed.
    Type: Grant
    Filed: April 21, 2000
    Date of Patent: December 17, 2002
    Assignee: University of Wales Aberystwyth
    Inventors: Christopher Lyndon Davey, Douglas Bruce Kell
  • Patent number: 6483323
    Abstract: A projectile fuze detects transitions between target layers by an electronic antenna radiating laterally into the target material and coupled to a pullable oscillator whose frequency shifts as the target material changes while the projectile penetrates. A frequency shift threshold detector relates the observed frequency shifts to a stored target profile to detonate the projectile after the desired layer penetration.
    Type: Grant
    Filed: January 16, 1996
    Date of Patent: November 19, 2002
    Assignee: General Dynamics Decision Systems, Inc.
    Inventors: Monty W. Bai, Gerald James Moore, Ralph Eugene Foresman
  • Publication number: 20020118026
    Abstract: Measurement of the permittivity of thin films is facilitated through the use of a short cylindrical metal cavity containing parallel plates between which a specimen to be measured is placed. The use of such parallel plates contained within such a cavity is particularly advantageous when swept frequency measurement methods utilizing frequency ranges from 0 to 20 GHz are employed. A test fixture which is preferred for use in providing such a cavity is disclosed as are methods of using the test fixture.
    Type: Application
    Filed: December 28, 2000
    Publication date: August 29, 2002
    Inventor: Yutaka Doi
  • Publication number: 20020113603
    Abstract: The present invention comprises a sensor apparatus used to measure surface mechanical loading such as a liquid loading that compensates for static capacitance in the sensor. The sensor includes a resonator and a variable capacitance device. The resonator and its concomitant circuitry has a static capacitance and is adapted to increase its motional impedance when exposed to surface mechanical loading. The variable capacitance device is connected to the resonator and is adapted to compensate for the static capacitance, whereby the range and linearity of the sensor apparatus are improved.
    Type: Application
    Filed: December 28, 2000
    Publication date: August 22, 2002
    Inventor: James J. Spates
  • Patent number: 6414497
    Abstract: A paving material analyzer system is disclosed that uses paving material impedance to determine paving material density. The invention also includes a method for analyzing paving material, in particular, determining paving material density. The paving material density can also be used to determine a percentage of maximum compaction. A paving material analyzer is also disclosed that determines paving material density regardless of moisture presence on the paving material.
    Type: Grant
    Filed: May 4, 2000
    Date of Patent: July 2, 2002
    Assignee: TransTech Systems, Inc.
    Inventors: Robert A. Sovik, Richard N. Hosterman, George G. Moross
  • Patent number: 6046623
    Abstract: Between a reference voltage point and the emitter or the source of a transistor of which the collector or the drain is connected to a power source and to which an signal is input at its base or its gate, DC current passing means for causing a current to flow from the emitter or the source to the reference voltage point and a capacitor connected to the reference voltage point at one end and charged with a voltage generated in the DC current passing means are provided. A detection output for the signal is obtained from the emitter or the source of the transistor, or the other end of the capacitor.
    Type: Grant
    Filed: November 13, 1997
    Date of Patent: April 4, 2000
    Assignee: Alps Electric Co., Ltd.
    Inventor: Kazuo Hasegawa
  • Patent number: 5625294
    Abstract: An apparatus for detecting seated condition for toilet seat which detects whether the change in input voltage of determining circuit, over predetermined time, in response to electrostatic capacity is existed or not. When the change is existed, the present apparatus computes and renews the set value 1 for detecting un-seated condition and the set value 2 for detecting seated condition based on the changed input potential.Accordingly, the present apparatus is the apparatus for detecting whether a human is seated or un-seated on a toilet seat using electrostatic capacity and the present invention can reduce the error in detection caused by the change in electrostatic capacity owing to a person, temperature and humidity.
    Type: Grant
    Filed: November 18, 1994
    Date of Patent: April 29, 1997
    Assignees: Aisin Seiki Kabushiki Kaisha, Inax Corporation
    Inventors: Shinji Kawai, Mitsugu Nonomura, Yuji Yamaguchi, Seiji Tanaka, Akira Takamata
  • Patent number: 5592098
    Abstract: A tubular single-layer winding coil is installed on the outer periphery of a thin wall portion of a cylindrical container case and a columnar electrode is provided at the center of the inside of the cylindrical container case. A fuel channel is formed between the coil and the electrode so that the permittivity of fuel flowing through the fuel channel is detected from the electrostatic capacity therebetween. Further, variation of the electrostatic capacity due to the temperature characteristics of the fuel is compensated by the temperature characteristics of the permittivity of the thin wall portion of the sensor unit. Furthermore, variation of the electrostatic capacity due to the temperature characteristics of the fuel is compensated by the temperature compensation capacitor which is connected with the single layer winding coil in parallel.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: January 7, 1997
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hiroyoshi Suzuki, Akira Okada, Takahiro Moronaga
  • Patent number: 5543722
    Abstract: A tubular single-layer winding coil is installed on the outer periphery of a thin wall portion of a cylindrical container case and a columnar electrode is provided at the center of the inside of the cylindrical container case. A fuel channel is formed between the coil and the electrode so that the permittivity of fuel flowing through the fuel channel is detected from the electrostatic capacity therebetween. Further, variation of the electrostatic capacity due to the temperature characteristics of the fuel is compensated by the temperature characteristics of the permittivity of the thin wall portion of the sensor unit. Furthermore, variation of the electrostatic capacity due to the temperature characteristics of the fuel is compensated by the temperature compensation capacitor which is connected with the single layer winding coil in parallel.
    Type: Grant
    Filed: July 25, 1994
    Date of Patent: August 6, 1996
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hiroyoshi Suzuki, Akira Okada, Takahiro Moronaga
  • Patent number: 5418467
    Abstract: This invention concerns an apparatus for checking the thickness and uniformity of a coating made of conducting material deposited on an elongated insulating body, this apparatus comprising:a sensor sensitive to the presence of the elongated body and forming part of an electrical circuit powered by a power supply voltage (24),measurement instruments (25) to measure an electrical quantity that is a function of the thickness of the conducting coating, at the output of the circuitequipment for processing the electrical quantity to deduce the thickness of the conducting coating,wherein the sensor consists of a condenser (10) containing two plates separated from each other by an air gap containing a dielectric material, this condenser being adapted to enable the elongated body to pass through the air gap.
    Type: Grant
    Filed: June 25, 1993
    Date of Patent: May 23, 1995
    Assignee: Alcatel Fibres Optiques
    Inventors: Bernard Floch, Patrick MacKenzie
  • Patent number: 5414368
    Abstract: A dielectric constant detecting apparatus comprises an LC circuit for shifting the phase of a high frequency voltage signal according to the dielectric constant of a liquid which passes between the coil and the electrode of the LC circuit. A resistor is connected between the LC circuit and at least one part of a phase comparator. The phase comparator detects the phase shift between high frequency signals provided at both ends of the resistor. The resistor and at least one part of the phase comparator are integrally included in an insulator. The output of the phase comparator is compared with a predetermined phase shift value. A voltage control device adjusts the high frequency voltage signal from the voltage applying device so that the phase shift detected by the phase comparator is further adjusted toward the predetermined phase shift value.
    Type: Grant
    Filed: September 10, 1992
    Date of Patent: May 9, 1995
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Kenji Ogawa, Hiroyoshi Suzuki
  • Patent number: 5397994
    Abstract: A particulate moisture measurement gauge of the type using a resonant electric circuit connected to a diode detector and to an AC signal generator having a frequency near the resonant frequency of the resonant circuit and in which the resonant circuit is electrically coupled to the particulate by a capacitor having the particulate as its dielectric. A probe is formed as a transmission line having a length which is approximately an integral number of one quarter wave lengths long. One end of the transmission line is connected to the circuitry and its opposite, moisture sensing end is immersed in the particulate. Preferably the probe is a rigid, conductive tube with a central rod having a ceramic insulator sealing its moisture sensing end and the circuitry housed in its opposite end.
    Type: Grant
    Filed: December 28, 1993
    Date of Patent: March 14, 1995
    Assignee: Alkon Corporation
    Inventor: Robert W. Phare
  • Patent number: 5325067
    Abstract: It is an object of the present invention to prevent variations in sensitivity of the sensor circuits of the respective channels by equalizing the power of oscillation frequency signals to be distributed/supplied from one oscillation circuit to the sensor circuits of the respective channels. Multi-channel sensor circuits are arranged with a common oscillation circuit. A high-impedance conversion circuit is connected to the output terminal of the oscillation circuit. A first impedance matching circuit for performing impedance matching of resonance circuits of the respective channels with reference to the oscillation circuit is arranged on the output side of the high-impedance conversion circuit. Second impedance matching circuits for performing impedance matching of the oscillation circuit with reference to the resonance circuits are connected at the input terminals of the resonance circuits of the respective channels.
    Type: Grant
    Filed: May 25, 1993
    Date of Patent: June 28, 1994
    Assignee: Murata Mfg. Co., Ltd.
    Inventors: Noboru Masuda, Tetsuo Oosawa, Yasutaka Fujii
  • Patent number: 5321366
    Abstract: A plurality of sensor circuits each including an oscillator circuit, a detection electrode, and a ceramic resonator for changing a resonance frequency in accordance with a change in small electrostatic capacitance detected by the detector electrode and outputting a detection signal corresponding to a change in resonance frequency are formed on a circuit board. Detector electrode surfaces A.sub.1 to A.sub.4, B.sub.1 to B.sub.4, and C.sub.1 to C.sub.4 of the first to third sensor circuits are formed on the upper surface of the circuit board in a divisional manner. The detection surfaces of the respective sensor circuits are arranged to have codes in the scanning direction of an object to be detected. The fixed capacitances of the detection surfaces are decreased, and a change of state of the object can thus be detected at a high resolution.
    Type: Grant
    Filed: August 31, 1992
    Date of Patent: June 14, 1994
    Assignee: Murata Mfg. Co. Ltd.
    Inventors: Masuda Noboru, Oosawa Tetsuo, Fujii Yasutaka
  • Patent number: 5276431
    Abstract: A security tag for use with an electronic security system is used for attachment to an article having an inherent capacitance such as meat. The security system includes a transmitter for transmitting into a surveilled area electromagnetic energy having a center frequency within a predetermined detection frequency range and a receiver for detecting within the surveilled area the presence of a security tag resonating at a frequency within the detection frequency range in response to the electromagnetic energy. The tag includes a generally planar dielectric substrate having a first side and a second side. Circuitry on the substrate establishes a resonant circuit having a resonant frequency which is initially a predetermined frequency interval above the center frequency of the detection frequency range.
    Type: Grant
    Filed: April 29, 1992
    Date of Patent: January 4, 1994
    Assignee: Checkpoint Systems, Inc.
    Inventors: Anthony F. Piccoli, Gary T. Mazoki
  • Patent number: 5269175
    Abstract: The invention relates to a sensor with two electrodes and a non-conducting iaphragm arranged between them. The electrodes have an insulating coating, which preferably comprises a metal oxide, mixed metal oxide, metal nitride, inorganic insulating material or fluorocarbon and the non-conducting diaphragm a metal oxide, mixed metal oxide, inorganic or organic insulating materials. As a function of the intended use, the diaphragm and electrode coating are porous (for measurements in non-aqueous liquids) or non-porous (for measurements of aqueous liquids). It is also directed at a process for measuring the characteristics of a liquid with the sensor according to the invention, as well as to the use of the sensor for the continuous or discontinuous investigation of liquids.
    Type: Grant
    Filed: July 29, 1991
    Date of Patent: December 14, 1993
    Assignee: Fraunhofer-Gesellschaft zur Forderung der angewandten Forschung e.V.
    Inventors: Horst Chmiel, Gunter Hellwig, Herbert Bauser
  • Patent number: 5245295
    Abstract: Disclosed is a method of detecting a variation in stray capacitance by use of a PLL circuit.
    Type: Grant
    Filed: July 13, 1992
    Date of Patent: September 14, 1993
    Assignee: Jalco Co., Ltd.
    Inventors: Shuji Hata, Osamu Murasawa
  • Patent number: 5231359
    Abstract: A ceramic resonance type electrostatic sensor apparatus with an oscillator at a fixed frequency including a first ceramic resonator which has a fixed resonance frequency, a detecting unit for detecting a capacitance between the detecting unit and an object to be detected, a resonating circuit including a second ceramic resonator and having a resonance point which varies with the small change in capacitance detected by the detecting unit, a high impedance circuit connected between the oscillator and the resonating circuit, and a high impedance circuit connected between the resonating circuit and the detecting circuit.
    Type: Grant
    Filed: May 18, 1990
    Date of Patent: July 27, 1993
    Assignee: Murata Mfg. Co., Ltd.
    Inventors: Noboru Masuda, Tetsuo Ohsawa, Takashi Sugimura
  • Patent number: 5198777
    Abstract: Apparatus for detecting thickness which includes an electrode detecting unit including a ground electrode and a detecting electrode. The electrodes oppose each other along a paper path. An oscillating circuit provides an oscillation frequency signal. A resonant circuit, having a resonator independent of the oscillating circuit, has a resonance point which changes in accordance with a change in electro-static capacitance corresponding to a change in paper thickness detected by the electrode detecting unit. A resonant circuit outputs a detection signal corresponding to the change in resonance point. By analyzing this detecting signal, a state of two sheets of paper passing through the path is detected as a change in paper thickness.
    Type: Grant
    Filed: February 12, 1991
    Date of Patent: March 30, 1993
    Assignee: Murata Mfg. Co., Ltd.
    Inventors: Noboru Masuda, Tetsuo Oosawa, Yasutaka Fujii
  • Patent number: 5196799
    Abstract: A method and apparatus for the non-destructive testing of a protective baer material. In a preferred embodiment, the method comprises applying an alternating electrical current across the protective barrier material for establishing a conductivity, G, of the protective barrier material and/or a quality factor, Q, of the protective barrier material. The conductivity, G, and/or the quality factor, Q, are measured at more than one frequency. The quality factor and/or conductivity measurements so obtained at the more than one frequency are compared to predetermined quality factor and/or conductivity limits.
    Type: Grant
    Filed: July 12, 1990
    Date of Patent: March 23, 1993
    Assignees: Drexel University, United States of America as represented by the Food & Drug Administration
    Inventors: Richard B. Beard, Robert Schmukler, Herman P. Schwan, Frederick Prout
  • Patent number: 5157337
    Abstract: A dielectric constant measurement probe assembly includes a coaxial cable ving a outer electrical conductor and a center electrical conductor extending within the outer conductor and terminating at an end portion which projects beyond an end portion of the outer conductor. An adapter member has a central passage receiving the coaxial cable with the outer conductor of the cable extending through the passage of the adapter member and projecting therefrom. An outer tube has a bore composed of first and second axial sections. The second bore section is smaller in diameter than the first bore section. The adapter member is inserted in the first bore section with the end portion of the coaxial cable outer conductor inserted into the second bore section and making electrical contact therewith such that the outer tube thus constitutes an extension of the outer conductor.
    Type: Grant
    Filed: October 3, 1990
    Date of Patent: October 20, 1992
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Michael M. Neel, Frank J. Schiavone
  • Patent number: 5150062
    Abstract: The electrostatic capacitance sensing circuit comprises a resonance circuit composed of an electrode capacitance formed by a substance to be measured and sandwiched between two opposing electrode plates and an inductance at least part of which is connected in parallel to the electrode capacitance; an active element (e.g. transistor) for constituting an oscillator in cooperation with the resonance circuit; and in particular a capacitor connected between the resonance circuit and the active element. Since a dc bias voltage of the active element is substantially not applied to the electrode plates, it is possible to prevent electrolytic corrosion of the electrode plates due to electromotive force generated between the electrode plates when ions are resolved into the substance to be measured and therefore the substance changes to an electrolytic solution.
    Type: Grant
    Filed: January 2, 1991
    Date of Patent: September 22, 1992
    Assignee: Nissan Motor Co., Ltd.
    Inventor: Kiyoshi Takeuchi
  • Patent number: 5038110
    Abstract: A capacitive difference sensor includes two sensor electrodes, each of which lies opposite a transmitting electrode fed by an electrical AC voltage source. A circuit arrangment connected to the two sensor electrodes for signal recovery generates a differential signal which corresponds to the difference between the displacement currents induced in the two sensor electrodes. The circuit arrangement includes a series resonance circuit comprising a coil and a capacitor, the resonance frequency of the series resonance circuit corresponding to the frequency of the AC voltage source. The two sensor electrodes are coupled via a transformer in opposite senses to the series resonance circuit and the differential signal is tapped off at the tap of the series resistance circuit formed by the connecting point between the coil and the capacitor.
    Type: Grant
    Filed: June 26, 1989
    Date of Patent: August 6, 1991
    Assignee: Endress u. Hauser GmbH u. Co.
    Inventors: Hans Braun, Uwe Kessler
  • Patent number: 4912976
    Abstract: A liquid level sensing system comprising a probe and a reactive element carried by the probe. The reactive element forms a portion of a tuned circuit in a voltage-controlled oscillator. The output of the voltage-controlled oscillator is compared to a fixed frequency reference signal and a frequency/phase detector generates a signal indicative of any difference. The frequency/phase detector output is applied to the voltage-controlled oscillator to maintain the output frequency of the oscillator at the frequency of the reference signal. The output of the frequency/phase detector is also differentiated to develop a pulse when the frequency/phase detector output signal varies rapidly, indicating initial contact between the probe and the surface of a liquid held within a container.
    Type: Grant
    Filed: June 26, 1987
    Date of Patent: April 3, 1990
    Assignee: Beckman Instruments, Inc.
    Inventor: Donald P. Labriola, II
  • Patent number: 4914377
    Abstract: A capacitance probe extends into a container for material which increases the capacitance between the probe and the container when the material contacts the probe. A fixed RF voltage is supplied to the base of a transistor in an electronic translator having a capacitor between the probe and the transistor's emitter. A first diode conducts between the base and RF ground. A second diode conducts between the emitter and the base. A small-value capacitor is connected between an ungrounded DC supply terminal and the probe. A third diode conducts variable DC to the transistor's collector from a variable DC signal line supplied with DC for the DC terminal through a resistor. A comparator has a first input connected to the line and a second input connected to a reference voltage. The comparator's output is adapted to energize an output signal and a relay when the DC signal on the line drops below the reference voltage.
    Type: Grant
    Filed: August 25, 1988
    Date of Patent: April 3, 1990
    Assignee: Ludlow Industries, Inc.
    Inventor: Craig A. Russell
  • Patent number: 4908574
    Abstract: A sensor for sensing and quantifying the conformity of a workpiece surface contour to a predetermined design contour. The sensor consists of an array of capacitor elements on a surface having the negative image of the predetermined design contour, against which the workpiece is mated. In operation, each of the capacitor elements and the workpiece are connected to a corresponding oscillator circuit so that the frequency of each circuit is a function of the capacitance between the individual plate element and the workpiece, while the capacitance is a function of the distance between the individual plate element and the workpiece. Hence the overall output of the circuits is a function of the conformity of the workpiece surface contour to the contour or topology of the sensor surface.
    Type: Grant
    Filed: July 29, 1988
    Date of Patent: March 13, 1990
    Assignee: Extrude Hone Corporation
    Inventors: Lawrence J. Rhoades, Donald Risko, Ralph L. Resnick