Abstract: A capacitance gauge system is described for determining the thickness of thin-film non-conducting material (i.e. polyethylene, vinyl, etc.). An elongated capacitance sensing head is applied to one side of the material being measured thereby disturbing the electric field produced by the head. Internal circuitry monitors the effect of the material under test and produces an output proportional to the variation in the material's thickness. A new method of resolving capacitance changes results in the ability to resolve capacitance changes on the order of 5.times.10.sup.-17 Farads in a linear manner with the benefits of simplicity, excellent stability, low power requirement, and small physical size. These factors allow said apparatus to be incorporated into a small hand-held unit. Because of this advancement in portability, accurate measurements can be made more quickly and conveniently than previously possible.

Abstract: An apparatus and method for testing the integrity of wiring cables provides a transmitter and a receiver that electrically connect to opposite ends of group of wires to be tested. The transmitter produces a voltage test signal applied to a test set of wires and a different voltage reference signal is applied to a reference set of wires. At the receiver, indicator circuits interconnect the wires to a common bus. The reference signal is applied to the common bus and, when the test signal is present, the indicators operate to produce a display. The test signal can be cycled through a plurality of test sets making up the entire test group.

Abstract: A noise rejection circuit improves the signal-to-noise ratio of a ratiometric measurement circuit. A first operational amplifier produces a scaled-up voltage proportional to a low reference voltage. The scaled-up voltage is applied to a series connected reference resistance, whose value is known, and a resistance whose value is unknown and is to be measured. A parameter voltage formed across the resistance is applied to second operational amplifier acting as a buffer. A buffered parameter voltage is scaled down by a voltage divider. The scaled-down voltage is applied to a ratiometric converter, that produces an output representative of the unknown resistance value. The ratio of a first pair of resistors that determines the gain of the first operational amplifier is the same as the ratio of a second pair of resistors that form the voltage divider, such that the low reference voltage is scaled up and the parameter voltage is scaled down by the same factor.

Abstract: An electrical gauge structure capable of conveniently placing thereon one or two measuring bars is provided. The structure includes a housing, a fixing piece cooperating with the housing to define therebetween a clearance, and two retaining pieces provided on two sides of the fixing piece and limitedly slidably guided in the clearance so that when the retaining pieces are outwardly slid, they can position thereon the measuring bars.

Abstract: A method and means for determining the deflection of a movable element in a transducer by measurement of capacitance. The result is independent of extraneous capacitance between the transducer terminals and the environment, of the magnitude of the transducer capacitance, and of scaling factors within the measurement circuits. The difference and sum of differential capacitances are determined, preferably independently of their individual values, using switching techniques and a common measurement circuit. The ratio of differential capacitances is determined by causing the measurement signal for one capacitance to be inversely proportional to the magnitude of the other capacitance.

Abstract: A high-voltage measuring device includes a grounded, cylindrical outer electrode (1) and an inner coaxial electrode (2) which has an at least approximately cylindrical shape and carries a high-voltage potential. A non-flat high-voltage resistor (3) which is arranged coaxially with respect to the inner electrode and is connected thereto. This resistor extends at least as far as the vicinity of the outer electrode. The response bandwidth and the loadability of the device substantially improved in that the high-voltage resistor is a cone shape envelope of uniform thickness such that the potential variation in response to current flow through the resistor corresponds to the electrostatic potential variation at least at the area of the inner electrode.

Abstract: A bridge-type capacitance transducer is disclosed. The transducer utilizes a coaxially mounted circular stator and circular rotor to form the capacitance bridge. An excitation voltage is applied to the bridge. The output voltage of the bridge is conditioned by synchronous detection so as to yield a signal proportional to the degree of rotation of the rotor.

Abstract: A cable tester for testing the individual conductors of a multiconductor cable. The cable tester includes a transmitter for connection to one end of the cable and a receiver for connection to the opposite end of the cable. The receiver includes a microprocessor having an EPROM memory. The receiver also includes an LCD display and a key pad for data input. In use the transmitter sequentially generates voltage pulses through each conductor of the cable and to the receiver. The receiver monitors these pulses at the opposite end of the cable and feeds this data into the microprocessor for processing and display on the LCD display. The cable tester quickly detects shots, opens, or crossed conductors within the cable and provides results of the testing on the LCD display.

Abstract: A humidity sensing apparatus which includes a humidity sensor which detects humidity as a function of impedance is provided. A reference resistor has a predetermined resistance value. A charge switching circuit selectively couples one of the reference resistor or the humidity sensor in series with a reference capacitor which has a predetermined capacitance. A voltage judging circuit determines whether the terminal voltage of the reference capacitor is high or low. A charge/discharge switch selectively charges and discharges the reference capacitor in accordance with the output of the voltage judging circuit. A sensor direction switching circuit inverts the direction of current flowing through the humidity sensor during charging of the reference capacitor. An oscillation frequency counter counts the number of charge/discharge cycles which are repeated during a predetermined time period.

Abstract: An apparatus for providing a precise, continuous, and dynamic measurement of the electrical resistivity of a liquid medium. A dynamic measurement cell is provided with at least one conduit of electrically insulating material in which a conductive electrode slides with a motion of given amplitude. The lower portion of the conduit is calibrated over a length equal to at least the given amplitude, and has a known cross-section. The cell is immersed in a crucible containing the liquid medium for test at constant temperature to monitor various electric parameters. The monitoring system provides devices for controlling, adjusting, and measuring the amplitude and speed of the displacement of the electrode; measuring and adjusting the depth of immersion of the electrodes; and, measuring the variation, in ohmic resistance, of the cell as a function of the displacement of the electrodes. The conductivity is determined by an equation proportional to the ratio of the change in amplitude to the change in resistance.

Abstract: A method and apparatus for determining the extent of deflections of a movable diaphragm in a capacitive displacement type transducer. The transducer circuit is connected to a three terminal capacitive type transducer, and produces an output which is essentially of stray capacitances, circuit component tolerances and changes, and dimensional changes in the transducer elements caused by temperature changes. This is achieved by providing an output which is representative of the difference in the capacitances of the two transducer capacitors, nominalized by dividing by the sum of the capacitance reciprocals. The output of the transducer circuit thus represents the extent of the diaphragm deflection with all other transducer and circuit parameter variations removed.

Abstract: An impedance meter with improved measurement accuracy obtained by controlling the level of the signal source. The impedance meter comprises a signal source, feedback amplifier, synchronous detector, A/D and control logic. The source level is maintaind by the control logic at a predetermined value by measuring the output of a synchronous detector and intermittently adjusting the level of the source thereby compensating for variations in test object's impedance. Control logic algorithms employed include successive substitution, bisection and linear interpolation.

Abstract: Method for determining qualities and/or frequencies of electrical tuned circuits. The method includes the steps of exciting the turned circuit with a switching pulse which has a short rise and fall time as compared with a period corresponding to the resonant frequency of the circuit, and evaluating the oscillation dying out after the switching impulse.

Abstract: A meter driving apparatus used for automotive meters such as a tachometer and a speedometer. The frequency of a pulse signal the period of which changes in correspondence with an input is calculated by counting the reference clock signals. A current corresponding to the calculated frequency is applied to two exciting coils which are orthogonal to each other, and the indicator points at the direction at the angle determined by the torque received in accordance with the magnetic field generated. A time counter adds one to the current count value whenever a predetermined time has elapsed. Even when the input pulse signal has a low frequency and the frequency rapidly changes from a high value to a low value, a temporary output is calculated from the current count value so as to prevent the degradation of the responsiveness.

Abstract: Two lead wires for each, connected to opposite ends of a heat generating element are secured to a holder. These lead wires form four-point-terminals at their other ends and thereby a disposable sensor is provided. A current source and a voltmeter are connected to the terminal and changes in various properties of fluid are determined on the basis of a value of current supplied from the current source and a value of voltage measured by the voltmeter.

Abstract: An amperometric method for the direct measurement of acidity in a medium which contains at least one ester of an acid containing oxygen, and whose dielectric constant is lower than 30. The method provides for maintaining a constant voltage between an ultramicroelectrode and a counterelectrode and measuring the current therebetween as an increasing quantity of diphenylphosphoric acid is added to the medium via a microburette. The measured current being indicative of the acidity of the medium under test. A predetermined curve is provided which represents the relationship between the acidity of the medium and the current measured by the system.

Abstract: A conductivity detector includes an A.C. voltage supply and control circuit for applying a pair of electrodes disposed within a cell filled with electrolyte with a predetermined A.C. voltage and a correction signal generating circuit for generating a A.C. reference signal. At an auto zero adjustment operation, an output A.C. current signal flowing through the electrolyte is detected and the A.C. current is added to the A.C. reference signal. In advance of measuring conductivity, the amplitude of the A.C. reference signal is corrected until the resultant signal of the A.C. output current and the A.C. reference signal reduces to zero.

Abstract: The present invention is comprised of a non-intrusive microwave sensor system for measuring fluid saturation or multiple fluids contained within a flowline or a fluid saturated porous medium. Here, the microwave oil saturation scanner (MOSS) comprises a transmit portion and a measurement portion. The transmit portion generates two signals for different purposes. The first signal is used as a reference signal upon which the sample signal is eventually compared. The second signal is transmitted through the sample which causes a phase angle shift and signal attenuation. The two signals are then compared in the measurement portion where the phase angle shift and the signal attenuation is related to the concentration of oil and water in the sample mixture.

Abstract: An apparatus for measuring the resistance of a test specimen includes an insulated-gate-bipolar-transistor (IGBT transistor) which is provided for applying a test current to the test specimen. A voltage measuring unit is provided including a serial connection of a voltage measuring device and an MOS transistor. A current measuring device is provided for measuring the test flowing through the test specimen. The voltage measured by the voltage measuring unit is used to compensate for the voltage drop across the IGBT transistor when calculating the resistance of the test specimen.

Abstract: A wye-type air-core gauge system provides magnitude indications of measurands in response to PWM signals generated by a control unit that receives electrical signals from a sensor that represents magnitude variations of the measurand. The size of the stator coils of the gauge makes possible a very low profile gauge suitable for mounting in an instrument cluster.