Abstract: Disclosed are a soil monitoring sensor and a method of operating the same. The soil monitoring sensor includes a first probe formed to extend in a first direction, and including a first electrode and a second electrode; a first resonance circuit connected to the first electrode and the second electrode of the first probe, and configured such that a first AC signal is applied thereto; a second resonance circuit having the same impedance as the first resonance circuit, and configured such that a second AC signal is applied thereto; and a determination circuit configured to receive a first electrical signal formed in the first resonance circuit, to receive a second electrical signal formed in the second resonance circuit, and to generate a first determination value for the state of the soil based on the first resonant frequency and the second resonant frequency.

Abstract: The present invention is a sensor device comprising: a housing; a processing unit assembly disposed within the housing, wherein the processing unit comprising a high frequency oscillator, a first voltage meter, a low frequency oscillator, a second voltage meter; a probe having a predetermined shape and profile attached to the processing unit and extending from the housing a predetermined distance; and a first sensing unit integrated into the probe and in electrical communication with the high frequency oscillator and the first voltage meter; a second sensing unit integrated into the probe relative to the first sensing unit and in electrical communication with the low frequency oscillator and the second voltage meter.

Abstract: A method for identifying and characterizing a condensate entrained in a fluid using time domain analysis and frequency domain analysis to identify individual volume fraction constituents and condensates within a pipe on a real time basis and to measure the volume of the individual volume fraction constituents and condensates flowing through the pipe on a real time basis.

Abstract: Provided here are methods, apparatuses, and systems directed to the determination of geochemical properties of liquid hydrocarbons based on the dielectric properties of components of the liquid hydrocarbons using microwaves. Also disclosed is a method for characterizing a geochemical property of a liquid hydrocarbon by measuring the dielectric responses from a portion of the liquid hydrocarbon at different predetermined temperatures in two or more microwave resonant cavities to electromagnetic waves at select microwave frequencies, and determining a geochemical property of the liquid hydrocarbon in response to measurements of the dielectric responses.

Abstract: A fluid analysis device including a fluid receipt chamber, a first capacitive element for measuring fluid flow into the fluid receipt chamber and a controller operatively coupled to the first capacitive element, wherein the controller is configured to measure a first capacitance of the first capacitive element.

Abstract: A steam quality meter includes a pipe with an inlet and an outlet. A rod is located within the pipe between the inlet and the outlet. The rod defines an annular flow passage between an outer wall of the rod and an inner wall of the pipe. A mixing device is located within the pipe between the inlet and an upstream end of the rod. Spaced sensors are located within the annular flow passage. Each sensor is configured to sense capacitance and/or impedance of steam flowing through the annular flow passage.

Abstract: A capacitive sensor includes a sensing antenna electrode for capacitively coupling to a counterelectrode to form a capacitance, this capacitance being responsive to an electric-field-influencing property of an object or person proximate to the antenna electrode. The counterelectrode may be part of the capacitive sensor. The capacitive sensor also includes a capacitive sensing network connected to the antenna electrode to apply an oscillating signal thereto and to determine the capacitance based upon characteristics of the oscillating signal. The capacitive sensing network includes at least one inductor and a plurality of reactive components arranged to form a resonant network together with the capacitance, the plurality of reactive components being activatable and deactivatable in such a way as to modify a resonance frequency of the resonant network.

Abstract: A method for detecting electromagnetic waves derived from bacterial DNA, comprising extracting and purifying nucleic acids from a sample; diluting the extracted purified nucleic acids in an aqueous solvent; measuring a low frequency electromagnetic emission over time from the diluted extracted purified nucleic acids in an aqueous solvent; performing a signal analysis of the low frequency electromagnetic emission over time; and producing an output, based on the signal analysis, in dependence on the DNA in the sample. The DNA may be extracted from at least one of blood, feces, urine, saliva, tears, seminal fluid, sweat, seminal and vaginal fluids of a patient, or water to determine, e.g., potability. The samples may be frozen. The extracting and purifying may comprise diluting the sample with an aqueous buffer and mixing; degrading proteins in the diluted sample; precipitating DNA from the buffer solution; and resuspending the precipitated DNA in an aqueous solution.

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.

Abstract: A method for measuring a capacitance using a capacitance meter. The capacitance meter includes an AC power source with a controllable frequency which is fed to a capacitor to measure its capacitance. A first measurement of the capacitance is performed by the capacitance meter using a first frequency. When the first measurement of the capacitance indicates the capacitance is below a threshold capacitance a lower capacitance measurement is performed in the capacitance meter, using a second measurement of the capacitance using a second frequency. When the first measurement of the capacitance indicates the capacitance is above a threshold capacitance, a higher capacitance measurement is performed in the capacitance meter, using a second measurement of the capacitance using a third frequency, the third frequency being lower than the second frequency.

Abstract: A device, a system and a method for detecting an irregularity in a structure of an aircraft are proposed. The device includes a resonant circuit with a resonance frequency and a probe for tuning the resonance frequency of the resonant circuit. The resonant circuit and the probe are operatively connected in such a way that the probe changes the resonance frequency of the resonant circuit if the structure changes due to a formation of an irregularity.

Abstract: The invention relates to a device for touch/proximity detection, especially a capacitive switch device, which is designed to set switching states by approaching the switch device or by touching the switch device, in order to perform, for example, switching actions on an instrument. The invention also relates to a switch device, especially a switch device on a capacitive basis, for a cooktop, for operating the cooktop.

Abstract: A method for detecting electromagnetic waves derived from bacterial DNA, comprising extracting and purifying nucleic acids from a sample; diluting the extracted purified nucleic acids in an aqueous solvent; measuring a low frequency electromagnetic emission over time from the diluted extracted purified nucleic acids in an aqueous solvent; performing a signal analysis of the low frequency electromagnetic emission over time; and producing an output, based on the signal analysis, in dependence on the DNA in the sample. The DNA may be extracted from at least one of blood, feces, urine, saliva, tears, seminal fluid, sweat, seminal and vaginal fluids of a patient, or water to determine, e.g., potability. The samples may be frozen. The extracting and purifying may comprise diluting the sample with an aqueous buffer and mixing; degrading proteins in the diluted sample; precipitating DNA from the buffer solution; and resuspending the precipitated DNA in an aqueous solution.

Abstract: The invention relates to a device for determining at least one parameter of at least one medium, said medium being introducible into at least one measuring path. An electric and/or electromagnetic field can be partially coupled into or out of the medium by passing at least one electric and/or electromagnetic signal into the measuring path. The measuring path comprises at least one line arrangement having at least two elementary cells arranged along the measuring path, said elementary cells comprising at least one electric path from at least one input to at least one output and comprising at least one respective capacitative element. The electrical properties of the capacitative element can by be modified by the medium. The electric and/or the electromagnetic signal can be applied to the input of a first elementary cell and the output of the first elementary cell can be connected to the input of a second elementary cell.

Abstract: A method of determining level of a liquid between empty and full conditions within a container includes: providing first and second elongate capacitors, each capacitor being independently capable of measuring the liquid level at least between the empty and full conditions within the container, with the second capacitor being longer than the first capacitor; determining first and second capacitance values for the first and second capacitors, respectively, based on the liquid level height; and dividing the first capacitance value by a difference between the second and first capacitance values to thereby obtain a liquid level value independent of the dielectric constant.

Abstract: Devices and methods of the invention can be used in many industries, including, but not limited to, utilities, agriculture, food, textile, pharmaceutical, photovoltaic and semiconductor, medical devices, chemical and petro-chemical, material science, and defense, where monitoring and/or analysis of various properties of materials are desired. Sensors and methods of using same are provided for measuring at least one impedance of an object under test (or a tested object) at a predetermined frequency and/or a predetermined frequency range, particularly where resonance conditions are provided for such measurement.

Abstract: Disclosed herein is a method of interrogating a resonant circuit that includes embedding a resonant circuit into a material, wherein a dielectric of a capacitor of the resonant circuit is the material. The method includes remotely determining the resonant frequency of the electrical circuit with a measurement device, wherein the determining is accomplished automatically. Finally, the method includes remotely automatically determining at least one of an estimated or precise resistance of the resonant circuit, an estimated or precise quality factor of the resonant circuit, and an estimated or precise voltage ratio of the resonant circuit, wherein the voltage ratio is a ratio of a voltage of the energy absorbed by the receiver at resonance and a voltage of the energy absorbed by the receiver at a fixed frequency shift from resonance.

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.

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.

Abstract: Systems and methods for estimating a physical characteristic of a seafood product are provided. In one system, the estimate is based on a slope defined by a ratio of changes in peak resonant amplitude and frequency of an electromagnetic resonant circuit in loaded and unloaded states. In another system, a first probe of a plurality of probes is driven with a test signal when the plurality of probes is loaded by a seafood product and the estimate is based on received test signals at one or more of the other probes. In another system, the estimate is based on the loading effect of a seafood product on an electromagnetic resonant circuit, which is also used to read an ID from an RFID associated with the seafood product. The systems and methods may be used for individual specimens, or to determine an average estimate for multiple specimens at one time.

Abstract: An apparatus and method of detecting bio molecular by measuring a variation of an electrical characteristic of a circuit having an inductance device and a capacitance device. The bio molecular detection method comprises providing a signal converting unit having at least one inductance device and at least one capacitance device connected with each other, disposing a biochip, which has capturing probe biomolecules attached to a substrate, at a location in the signal converting unit, and measuring an electrical characteristic of the signal converting unit, performing a coupling reaction of the biochip and a sample to be analyzed; and measuring an electrical characteristic of the signal converting unit after the coupling reaction.

Abstract: Disclosed herein is a method of interrogating a resonant circuit that includes embedding a resonant circuit into a material, wherein a dielectric of a capacitor of the resonant circuit is the material. The method includes remotely determining the resonant frequency of the electrical circuit with a measurement device, wherein the determining is accomplished automatically. Finally, the method includes remotely automatically determining at least one of an estimated or precise resistance of the resonant circuit, an estimated or precise quality factor of the resonant circuit, and an estimated or precise voltage ratio of the resonant circuit, wherein the voltage ratio is a ratio of a voltage of the energy absorbed by the receiver at resonance and a voltage of the energy absorbed by the receiver at a fixed frequency shift from resonance.

Abstract: A system for sensing environmental conditions on a window assembly. The system includes a transparent panel and a sensor integrated onto the panel. The sensor being configured to sense environmental changes on the panel. The sensor may comprise conductive inks that are printed onto the window assembly. The window assembly may comprise a plastic panel, such as a multilayer polycarbonate panel such that a portion of the sensor may be located on the one layer of the panel while another portion of the sensor overlaps the first portion on a second layer of the window. The sensor may be a resistive or capacitive sensor and may be configured to detect changes in one or more environmental conditions, such as temperature or moisture. Further, the sensor may be in electrical communication with a controller configured for control various vehicle subsystems based on the sensor.

Abstract: The application concerns a measuring apparatus for determining a dielectric property, in particular the moisture and/or density, of a product, in particular tobacco, Cotton or some other fibrous product, having a measuring capacitor, a device for generating a high-frequency field in the measuring capacitor, which is influenced by a product which is arranged in a measuring volume of the measuring apparatus, and having a circuit device which includes the measuring capacitor and which is designed to determine suitable measurable variables of the high-frequency field influenced by the product, and is distinguished in that the circuit device is substantially non-resonant at the measuring frequency of the high-frequency field that is used, and measurement is based on the propagation of a travelling high-frequency wave in the measuring capacitor, and the circuit device is designed to determine two mutually independent measurable variables which are dependent on the amplitude and phase of the high-frequency wave infl

Abstract: A signal transmitting apparatus which makes exchanging information when pouring a liquid possible. A container body 201 of a transmitter side container 20 holds an electrically conductive liquid 402. A display 306 for confirming data reception is attached to a container body 211 of a receiver side container 21. The container body 201 and the container body 211 are electrically connected at a predetermined impedance by the liquid 402. Because digital data is modulated by a carrier of approximately 10 MHz, an electromagnetic field is generated. In particular, a return line 404 due to an electromagnetic near field is generated, and communications from the transmitter side container 20 to the receiver side container 21 becomes possible.

Abstract: The system comprises at least one electronic sensor for detecting the presence of moisture. The system further comprises at least one reading device for obtaining information from the sensor about the presence of moisture. The sensor comprises a resonant circuit which is at least partly formed from a moisture sensitive material, the electrical resistance of which increases when the material comes into contact with moisture. The reading device comprises transmitter-receiver means for generating an elecromagnetic interrogation field.

Abstract: A proximity switch which operates according to an inductive or capacitive action principle and contains a LC tuned circuit and a dynamically connected amplifier, and in which the approach of a suitable influencing element or article changes at least one oscillation parameter, the operating state of the amplifier being changed when the article does not reach a certain distance to the tuned circuit, the oscillation not however being interrupted with reaching the operating point. The proximity switch (1), likewise contains display elements (5) which are able to signal the presence of influence on the tuned circuit before the operating point or value of the amplifier is reached.

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: An oscillating device to determine the purity of single or multi-component liquids on the basis of their dielectric permittivity, in a continuous procedure through the frequency change in the static permittivity region and with strict temperature control. The oscillator is connected to a standard thermoregulated measuring cell, a frequency meter and a power source. The improved characteristic is that the circuit does not contain the usual micrometer and standard capacitors and that it has a previously determined inductance to improve measurement conditions. In this manner, and operating in the region of static frequencies to avoid relaxation phenomena, a continuous measurement is achieved with a high degree of precision that had never been previously obtained. A measurement procedure is also disclosed that is carried out with the device.

Abstract: A clock signal generator in an integrated circuit semiconductor device and a method of generating a clock signal, the clock signal generator comprising: a semiconductor substrate (2); an oscillator unit (4) which comprises at least one support member (10, 12) which is fixed relative to the substrate (2), an oscillator arm (6) which is oscillatably disposed to the at least one support member (10, 12) with regard a reference position, which oscillator arm (6) includes first and second conductive sections (6a, 6b) at positions extended from the at least one support member (10, 12), and at least one biasing element (14, 16) for biasing the oscillator arm (6) towards the reference position; a driver (18) which is disposed at the substrate (2) in spaced relation adjacent one of the conductive sections (6a) of the oscillator arm (6), which driver (18) is configured in use to drive the one of the conductive sections (6a) of the oscillator arm (6) towards or away therefrom when an electrical signal is applied thereto;

Abstract: The present invention relates to a system for nulling drive feedthrough error in a sensor having first and second drive electrodes which impart vibratory motion to first and second proof masses in response to first and second opposite phase drive signals, and having first and second capacitances defined between the drive electrodes and their associated proof masses. A mismatch between the first and the second capacitance is measured. Drive feedthrough caused by the measured capacitance mismatch is nulled by adjusting the relative amplitudes of the first and second opposite phase drive signals, whereby the ratio of the amplitudes is proportional to the ratio of the first and second capacitances. A servo loop may adaptively effect the ratio of amplitudes.

Abstract: The invention relates to a device and method for carrying out a contactless measurement of the conductivity of a liquid situated in a flow channel, and to the use of said device and method. According to the invention, the invention provides that a toroidal coil is precisely arranged around the flow channel. Said toroidal coil is interconnected with a capacitor to an oscillating circuit. The invention also provides that the electric characteristics of this circuit are then measured according to the conductivity which is sought after.

Abstract: An apparatus (100) for sensing presence and weight of a vehicle occupant includes a first conductor (120) that is electrically coupled to an oscillating circuit and disposed adjacent a first surface (112) of a compliant pad (110) within the seat of the vehicle. A first conductor (120) generates an oscillating signal at a first intensity. A second conductor (130) is disposed adjacent a second opposing surface (114) of the compliant pad (110) and is capable or receiving the oscillating signal at a second intensity. A detection circuit electrically coupled to the second conductor (130) and capable of receiving the oscillating signal at the second intensity determines the presence and weight of a vehicle occupant based upon the second intensity of the oscillating signal.

Abstract: An oscillating circuit to determine the purity of singlr or multi-component liquids on the basis of their dielectric permittivity, in a continuous procedure and through the frequency change in the static permittivity region. The oscillator is connected to a standard measuring cell, a frequency meter and a power source. The excluding characteristic is that the circuit does not contain the usual micrometric and standard capacitors and that it has a previously determined inductance to improve measurement conditions. In this manner, and operating in the region of static frequencies to avoid relaxation phenomena, a continuous measurement is achieved with a high degree of precision that had never been previously obtained. A measurement procedure is also disclosed that is carried out with said circuit.

Abstract: A position sensor comprises a capacitive transducer and an inductor connected in series with the transducer. The transducer is a differential capacitor whose total admittance is essentially independent of changes in the sensed position. The total capacitance and inductance resonate at the fundamental frequency of a generator that provides a drive voltage and the resulting voltage across the sensor is thus substantially greater than the drive voltage. This increases the current through the transducer, and consequently increases the sensitivity of the sensor.

Abstract: A position sensor determines relative changes in position of a first member and a second member. A first conductor is movable with one of the members and a second conductor is energized in response to a first electrical signal coupled to the first conductor across a gap. The coupling induces a current in the first conductor having a current value which varies in response to relative changes in the position of the first and second members. A power supply furnishes a predetermined supply voltage and a pulse generator generates output pulses at a predetermined repetition rate. A resonant circuit has a center resonant frequency within a range of resonant frequencies that include the repetition rate of the pulse generator. The resonant circuit generates the first signal with a voltage greater than the supply voltage so that the induced current value is sufficiently large to facilitate further processing.

Abstract: A combination fluid condition monitor and fluid level sensor having an excitation electrode divided into two segments disposed closely spaced and parallel to current sensing electrode. For the fluid condition monitoring mode function both segments of the excitation electrode are commonly excited sequentially at high and low frequencies and the currents sensed in the sensing electrode employed to compute the difference in impedance for determining the fluid condition. For the level sensing mode function a mode switching circuit grounds one of the excitation electrode segments and excites the other then grounds the other segment and excites the one segment and the resultant currents ratioed to determine the amount of electrode immersed in fluid and hence the fluid level.

Abstract: The present invention includes capacitive film thickness measurement devices and measurement systems. The invention also includes machines or instruments using those aspects of the invention. The present invention additionally includes methods and procedures using those devices of the present invention. The present invention discloses a capacitance measurement device and technique useful in determining lubricant film thickness on substrates such as magnetic thin-film rigid disks. Using the present invention, variations in lubricant thickness on the Angstrom scale or less may be measured quickly and nondestructively.

Abstract: A fluid condition monitor suitable for real time monitoring of a fluid in a fluid system such as on-board vehicle monitoring of engine oil and transmission fluid to determine contamination. A capacitive spaced array electrode probe is immersed in the fluid and an oscillating voltage is applied at a first frequency of at least one hertz and the current IB measured as an analog of the bulk fluid impedance. The voltage is also applied to the probe at a second frequency of less then one hertz and the current Is measured as an analog of the electrode surface impedance. The difference in measured currents &Dgr;I is determined electrically compared with a predetermined threshold value; and, the measured first frequency current IB is compared with an upper and lower limit value for IB determined empirically for the known baseline fluid.

Abstract: A recording medium suitable for use in an impedance matching apparatus adapted to a waveguide transmitting a microwave to a load. The apparatus includes detecting diodes and a computer. The recording medium includes a program, which includes predetermined approximate expressions. The predetermined approximate expressions recorded in the program correspond to the detecting diodes. The program causes the computer to compute an approximation value of input power to the waveguide using the respective predetermined approximate expressions and output voltages of the detecting diodes.

Abstract: In a wetness sensor for a window of a motor vehicle, a heating resistor arranged in the window and powered by DC current can be connected to a measuring device for measuring an AC impedance of the heating resistor, in particular the capacitive portion thereof. The impedance varies with the amount of wetness and, thereby, serves as a measure of the wetness. A capacitor is used to bring the sensor near resonance for improved sensitivity.

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.

Abstract: Apparatus for inspecting non-round annular containers includes elongated capacitive sensors, cooperating oscillators, which convert the sensor signal to a voltage corresponding thereto, and an electronic processor which receives the voltage and determines thickness. A displaceable electromechanical member is operatively associated with the sensor and emits an electrical signal corresponding to the degree of displacement of the sensor by a container being inspected. The electronic processor corrects the thickness determination by an adjustment of container diameter at the specific location where thickness is being monitored in order to compensate for container diameter variations due to the non-round characteristic of the container. In a preferred embodiment, linkage members secured to the rear of the sensor at a plurality of locations cooperate with a single displaceable element which converts the mechanical displacement of the sensor into a corresponding electrical signal.

Abstract: The invention relates to a moisture and salinity measurement and in particular to a sensor and its method or use which may provide values for the moisture/complex dielectric constant of a variety of mediums. A sensor apparatus is arranged for indicating the complex dielectric constant and conductivity of a medium and uses a tuned circuit. The tuned circuit oscillates such that the frequency of oscillation is representative of the complex dielectric constant of the medium.

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.

Abstract: A system (10) accurately measures the resistivity of a material (12) via capacitive coupling without contact with the material (12). A transmission electrode (14a) sends signals through the material (12) to a reception electrode (14b). An oscillation mechanism (16) forwards a periodic signal at a predetermined frequency f to the electrode (14a), and a detection mechanism (18) receives a resistivity signal from the electrode (14b), which signal is proportional to the resistivity of the material (12), and translates the resistivity signal into a resistivity value for the material (12). The oscillation mechanism (16) comprises an oscillator (21) connected through a transformer (T1) to a quarter-wavelength stub (24), which feeds an excitation signal to the transmission electrode (14a). The detection mechanism (18) comprises a detector (31) connected via a transformer (T2) to a quarter-wavelength stub (26), which is directly connected to the reception electrode (14b).

Abstract: This instrument contains a transducer and a sensor that are mounted on the exterior surface of a liquid container or tank. The transducer is tuned by electronic signals to the mechanical resonant frequency of the liquid container or tank. The sensor converts the mechanical vibrations into dynamic electrical signals using electronic components. A phase detector and feedback circuitry force the transducer to track the resonant frequency of the tank as liquid is removed from the tank. The signal output of the feedback control circuitry is converted to display the amount of liquid remaining in the tank. The resonant frequency of the liquid container is a measure of the total mass of the container. This includes the tare weight of the container plus the weight of the liquid in the tank. The tare weight of the tank is a constant. The stiffness of the tank can be considered a constant. The dampening coefficient changes do not adversely effect the accuracy requirements of the instrument.

Abstract: A detection apparatus for detecting a dielectric constant of fuel having an electrode disposed in a fuel passage and applied with an excitation signal, a monolayer-wound coil disposed in the vicinity of the electrode so that fuel is introduced in a space between the excitation electrode and the coil, a phase comparator which receives the signal to be applied to the excitation electrode and a signal induced in the coil to thereby compare the signals. The phase difference between both signals is detected using a low-pass filter to output the d.c. signal component of an output signal of phase comparator, a comparison integrator connected to the low-pass filter to output a controlled output signal so that the phase difference between the excitation signal and the induced signal in the coil becomes 90.degree.

Abstract: A system for leak detection in underwater structures wherein each critical leakage test point is maintained dry by an enclosure and a test cable is led down through the series of enclosures in fluid-tight manner to support a test probe within the dry test point volume. The test cable is a coaxial cable of selected characteristic impedance and each probe consists of a spirally wound, open-end dual pair supported on a plastic stub so as to constitute a parallel resonant circuit at a selected frequency. Thereafter, a test pulse is conducted down the coaxial cable and the impedance of any probe will be altered by the presence of water to produce a reflected pulse back up the coaxial cable to be detected and input to gating and counting circuitry to determine signal travel duration and, therefore, distance along the cable, as processing, printing and readout components provide output indications.