Abstract: An aerosol particle spectrometer utilizes a high voltage central electrode and a series of annular, axially arranged collector electrodes maintained at ground, for collecting positively charged particles suspended in an aerosol flowing between the electrodes. Each collector electrode provides current to an integrating electrometer including circuitry that rapidly charges and discharges the integrating capacitor during a brief reset cycle, to generate accurate particle characterizing information based on low currents, with high bandwidth and high dynamic range, virtually in real time.

Abstract: A method and a system is provided that includes a multifrequency generator supplying signals of at least three different frequencies to an electrode assembly, the capacitance of which is detected for a plurality of different frequency points. In this way, the capacitance of the electrode assembly, which is influenced by a substance present in the vicinity of the electrode assembly, may be reliably identified. Preferably, the conditions of a road surface may be reliably monitored.

Abstract: A method and a device is provided for controlling a switching converter comprising a high side switch and a low side switch. The method comprises testing the high side switch for a short circuit, and upon detection of a short circuit in the high side switch, leaving the switching converter in an operationally reliable state or shifting the converter to an operationally reliable state.

Abstract: A relative dielectric constant of a mixed substance consisting of powders and a liquid medium is calculated, and then the relative dielectric constant of the mixed substance or a relative dielectric constant of the liquid medium is calculated as a relative dielectric constant of the powders where the relative dielectric constant of the mixed substance becomes equal to a relative dielectric constant of the liquid medium. Therefore, the relative dielectric constant of the powders can be measured with high precision even in a high-frequency band in excess of several GHz.

Abstract: An apparatus for inspecting a sample for defects includes a signal generator for generating a signal and a device for splitting the signal into two separate signals which have substantially equal phase and magnitude. A sensor radiates the two signals on the sample and receives the two signals reflected from the sample. A device is provided for determining a difference between the two signals reflected from the sample without unwanted influence of variations of distance between the sensor and sample, and reflections from nearby sample edges and boundaries. A defect is determined to exist when a difference is found between the two reflected signals.

Abstract: A method and an apparatus is described to measure at least one physical parameter of a substance such as moisture and salt content. This is done by transmitting a microwave beam through the material to be measured and detect only a reflection of a predetermined polarity of the transmitted waves. To accomplish this a polarizing plate is used so that only cross-polarized microwaves, which pass through the substance are detected and the co-polar reflections from surrounding structures are excluded. The object can either be moving as on a conveyer belt or in a rest position.

Abstract: Embodiments test MOV arresters. One embodiment comprises applying a plurality of voltages to a high voltage lead of the MOV arrester, the plurality of voltages being changed between an initial test voltage and final test voltage (corresponding to a point of conduction of a reference MOV arrester); determining a resistive current through the MOV arrester for each of the voltages; determining information corresponding to the resistive current when the applied test voltage corresponds to the point of conduction of the reference MOV arrester; comparing the determined information with information associated with the point of conduction of the reference MOV arrester; determining that the MOV arrester has passed the test when the determined information corresponds to the information associated with the reference MOV arrester; and determining that the MOV arrester has failed the test when the determined information does not correspond to the information associated with the reference MOV arrester.

Abstract: There is provided a test apparatus including: a test module operable to supply test patterns to the electronic device; a main signal source operable to generate a first timing signal in accordance with a phase of the supplied timing signal and supply it to the test module; and a sub-signal source operable to receive the timing signal from the main signal source, generate a second timing signal for controlling timing at which the test module supplies the test patterns to the electronic device, and supply it to the test module. The sub-signal source includes a phase adjustment circuit that substantially uniforms the timing at which the main signal source outputs the first timing signal and the timing at which the sub-signal source outputs the second timing signal by delaying the timing signal received from the main signal source.

Abstract: The present invention provides an apparatus for measuring electrical impedance comprising: two input electrodes contacted to a subject for measuring impedance; a difference amplifier to which two signals inputted to the two input electrodes are inputted; a device for extracting a common mode component of two signals inputted to the two input electrodes; the third electrode contacted to the subject for measuring impedance; the first multiplier to which the common mode component is inputted; the first filter coupled with the first multiplier; the second multiplier coupled with the first filter; wherein a feedback signal outputted from the second multiplier is inputted to the third electrode.

Abstract: A process is disclosed for evaluating a measuring device comprising a capacitor (CM), with stages for charging the capacitor (CM) over an initial charging period (tk1, tk2) and for determining the capacitance charge as an initial measured value (tml). To determine a measuring condition that changes a normal state of the capacitance, e.g., moist as opposed to dry surroundings for the measuring cell, the process exhibits the following additional steps: charging the capacitance (CM) over a second charging period (tk2), which differs from the first charging period (tk1); determining the charge of the capacitance (CM) as a second measured value (tm2); and comparing the first and second measured values (tk1, tk2) to establish the comparative result.

Abstract: A simple and robust variable coaxial capacitive sensor and detection method for monitoring the position of a rapidly reciprocating member such as a piston or displacer in a free piston Stirling engine. The coaxial capacitor of the present invention in a preferred embodiment thereof is configured to modulate capacitive electrode area rather than inter-electrode spacing and as a result a highly linear transfer function can be achieved. Also disclosed are detection methods which derive and process signals in connection with applications which have small sensor capacitance variations while suppressing stray capacitance error.

Abstract: A switching circuit includes at least two first semiconductor switches, each having a first input portion and a second input portion; range resistors that are provided between output portions of the first semiconductor switches and a device under test and that have different resistances from each other; a second semiconductor switch having an input portion connected to the output portions of the first semiconductor switches; and a differential amplifier having an input portion connected to the output portion of the second semiconductor switch and an input portion connected to ends of the range resistors, the ends being adjacent to the device under test. In accordance with a control signal, a desired one of the first semiconductor switches is connected to the first input portion and the second switch is connected to the output portion of the desired first semiconductor switch.

Abstract: Film thickness measurement systems and methods are provided that utilize a signal generator having a Gunnplexer design and a resonant frequency detector to correlate the shift in resonant frequency experienced by a resonant cavity having one face abutting a test object. The shift is resonant frequency is determinative of a linear or near linear correlation between film thickness and the resonant frequency shift.

Abstract: An engine oil deterioration detection apparatus includes a sensing capacitor CS formed of paired electrodes dipped into engine oil whose deterioration is to be detected, the engine oil deterioration detection apparatus detecting deterioration of the engine oil on the basis of a change in electrostatic capacitance of the sensing capacitor CS. A measurement signal generation circuit generates a measurement signal to be supplied to the sensing capacitor CS. A detection signal output circuit outputs a detection signal on the basis of a response wave signal produced from the sensing capacitor CS in response to supply of the measurement signal thereto, the detection signal reflecting the electrostatic capacitance of the sensing capacitor CS. A temperature compensation mechanism is provided to compensate for a level change of the detection signal stemming from a temperature characteristic and/or a time-course deterioration of the detection signal output circuit.

Abstract: Sensor circuits for the measurement of small variations in the value of a sensing capacitor. An alternating voltage excites the sensing capacitor a predetermined frequency whereby the voltage on the sensing capacitor reverses polarity. This voltage on the sensing capacitor is sampled each time the voltage reverses polarity. An accumulator accumulates the sampled charges from the sensing capacitor. An output signal that represents the charge in the charge accumulating means indicates the measured capacitance.

Abstract: A moisture sensing apparatus includes an oscillator for supplying an AC signal to a driven ring of a sensor having a pad inside the ring, and a ground plate around the ring. An amplifier forms part of a temperature-compensated, precision rectifier, and is connected to the pad. A first diode connected to the output of the amplifier in a feedback loop of the amplifier, where the amplifier nullifies temperature variation effects upon the diode, and supplies a rectified signal which is a function of moisture content of material in contact with the sensor. A second diodes is connected between the amplifier output and other input of the amplifier. The sensor has a rounded configuration to avoid electrostatic field fringing effects, and a passive impedance with both resistive and capacitive members is connected in parallel with the sensor to provide a functional baseline for the rectified signal.

Abstract: A system and method detects coil-to-coil faults in an electric motor having a plurality of coils. The method includes applying a square wave signal to a first coil of the motor, connecting a capacitor and a resistor between ground potential and a second coil of the motor, applying the coil output voltage to an amplifying and peak detecting circuit, applying an output of the amplifying and peak detecting circuit to the input of the control unit and, after a delay period, generating a motor fault signal if the coil output voltage is below a predetermined threshold. The square wave signal is amplified by a circuit which prevents transmission of voltage signals from the coils to the output of the control unit during normal operation of the motor.

Abstract: The present invention relates to a single ended line testing method for qualifying an electrically conducting line. This method includes the steps of sending a plurality of excitation signals from a first end of the line towards a second end of the line and before the sending of this plurality of excitation signals, randomizing each excitation signal of the plurality of excitation signals. Subsequently, measurements are performed, at the first end of the line, of each reflection of the plurality of excitation signals sent towards the second end of the line. Then an inverse randomization on each of the measurements of reflections is performed which is succeeded by determining an average of all the measurements of reflections of the excitation signals. Finally, from the average a qualification of the electrically conducting line is determined.

Abstract: Oscillators have capacitors, respectively, whose capacitances change according to an external force and generate first oscillating signals according to the capacitances. Each of the capacitors is disposed, for example, between a substrate and a mass body that is movably disposed to face the substrate and oscillates in a direction perpendicular to the substrate. A detecting unit detects a relative difference between the capacitances of the capacitors as a difference between frequencies of the first oscillating signals. An angular speed or acceleration applied in a horizontal direction of the substrate is calculated according to the frequency change detected by the detecting unit. Therefore, a capacitance difference detecting circuit and a MEMS sensor that detect a minute change in the capacitances of the two capacitors caused by the external force are formed.

Abstract: In a method and apparatus for determining the moisture content of a material with a measuring line extending through the material and having a proximal end connected to a signal generator for supplying a pulse signal to the measuring line, which pulse signal is reflected and returned back to the proximal end of the measuring line to which a comparator is connected for measuring the travel time of the signal supplied, and the reflected signal returned, to the proximal end of the measuring line and its amplitude is with compared with an amplitude corresponding to a threshold, an adjustable threshold value generator and controller are provided generating a threshold value signal which depends on the amplitude of the reflected signal.