Abstract: A pulse discharge circuit for pulse testing an integrated-circuit device under test (DUT) is provided which uses three separate switching relays S1, S2, and S3, which are operated in a predetermined sequence. For charging the capacitance of a pulse-forming transmission line, the relay contact of S1 is closed while the relay contacts of relays S2, S3 are both open. For discharging the charge on the transmission line to form a test pulse, the relay contact of S1 is first opened, and the relay contact of S2 is then closed while the relay contact of S3 is open. After each test pulse is generated and applied to a DUT, the condition of the DUT is determined by a leakage current measurement. The relay contact S2 is opened to isolate the pulse generator circuit and then the relay contact S3 is closed.

Abstract: Apparatus is provided for continuously compensating for the dielectric absorption effect in a measuring capacitor in a circuit which employs means for charging the capacitor to develop an output signal thereacross and wherein the absorption effect causes an error in the output signal following a charging interval. The dielectric absorption effect is represented by at least one impedance branch connected in parallel with the capacitor and this branch includes a resistor and a capacitor connected together in series and having a RC time constant. Compensating means is provided having a correction means associated with the impedance branch and wherein the correction means continuously receives the output signal and provides therefrom a compensating signal. The correction means has a time constant that corresponds with that of the associated impedance branch. The compensating signal is combined with the output signal to provide a compensated output signal.

Abstract: A conductivity measuring device has a current source device connected to current supply elements through which a substantially square-wave current can be fed into a liquid, and a measuring circuit for determining the voltage drop in the liquid between voltage measuring elements.

Abstract: The invention is a method and apparatus for electrostatic potential sensing by using electromechanical microstructures. The mechanical microstructure may be fabricated by either surface micromachining or bulk-micromachining. The sensor comprises a movable plate which is movable in the lateral dimension and which is suspended from and above a substrate bearing an isolated electrically conductive layer. The layer acts as the sensor electrode and is brought in contact with or near the object the electrostatic potential of which is to be sensed. The movable plate is suspended between two fixed, suspended and cantilevered plates. The three suspended plates collectively form two capacitors with the two fixed plates comprising the first plate of first and second capacitors and the movable plate comprising the second plate of both capacitors.

Abstract: A circuit compares a difference between first and second voltages to a predetermined voltage. The circuit comprises an amplifier having first and second inputs. First and second capacitors are each coupled at one end to the first input of the amplifier. The first capacitor is charged with the first voltage and subsequently discharged. The second capacitor is charged with a first reference voltage and subsequently discharged. Third and fourth capacitors are each coupled at one end to the second input of the amplifier. The third capacitor is charged with the second voltage and subsequently discharged. The fourth capacitor is charged with a second reference voltage and subsequently discharged.

Abstract: An in situ probe failure detection method for probes which deliver an electric signal on account of a change of the concentration of a substance to be measured. An example of such a probe failure may be caused by, for example, fouling of the membrane as the relative change in signal may be interpreted as a change in the concentration of the substance to be measured. More particularly, the method involves detecting the need for calibrating probes, which probes deliver an electric signal on account of a change of the concentration of a substance to be measured, characterized by: (a) subjecting the probe to a stepwise change of the concentration of the substance to be measured; (b) calculating the value of the probe response time constant t.sub.c of the obtained measurement curve with the help of the following main equation (1): t.sub.c dy/dt=-y+.alpha..sub.0 +.alpha..sub.1 t wherein t=time (time), t.sub.c =probe response time constant (time), y=substrate probe signal (mass volume.sup.-1), .alpha..sub.

Abstract: A device for testing an electrical line by time domain reflectometry, using a pulse generator to generate a series of test pulses, a programmable delay generator which provides a delay in the transmission of the test pulses, and an analog to digital converter which samples the reflected signals from the line and sends them to memory. The test pulse is transmitted to the line and a number of digital sample values are produced sequentially at a defined sampling rate by the delay generator, which is incremented or decremented to advance or retard the transmission of the test pulse by 1/n times the sampling period, and sample values from each pulse obtained. The above steps are repeated until transmission of the test pulse has been retarded or advanced by at least (n-1)/n times the sampling period and sample values from each pulse obtained, with the sampled values arranged in order of increasing time difference between transmission of the test pulse and sampling.

Abstract: An apparatus (30) locates and measures any seam or other discontinuity (18) within a metal enclosure (10) by determining the characteristic inductance of the discontinuity. A pair of probes or electrodes (40, 42) are connected via a balun (46) to a network analyzer (56). When the probes are placed on either side of the discontinuity, the network analyzer can measure the length of the discontinuity by equating the discontinuity to an inductor.

Abstract: A method for testing a power bridge for an electric vehicle propulsion system, the power bridge including a switching circuit having first and second switching elements operable between "on" and "off" states. The method comprises the steps of selectively switching the first and second switching elements between the "on" and "off" states, monitoring the first and second switching elements to determine whether the first and second switching elements operate between the "on" and "off" states when selectively switched, and indicating a failure o#the switching circuit when at least one of the first and second switching elements does not operate between the "on" and "off" states when selectively switched.

Abstract: A differential conductivity recirculation monitor quantitatively determines the degree of recirculation in a fistula by comparing the conductivity of blood entering the fistula to the conductivity of blood being withdrawn from the fistula. A discrete quantity of a high conductivity marker fluid is injected into the blood entering the fistula, altering the conductivity of the blood entering the fistula. The altered conductivity blood enters the fistula and, if recirculation is present, co-mingles with blood in the fistula, altering the conductivity of the blood ion the fistula in proportion to the degree of recirculation. Blood withdrawn from the fistula has an altered conductivity related to the degree of recirculation. Quantitative values of the conductivity of the altered conductivity blood entering the fistula and the conductivity of the blood being withdrawn from the fistula are measured and a difference determined.

Abstract: A method and apparatus for simultaneously measuring the streaming potential of a fiber suspension and a filtrate thereof. A container is provided having an inlet and an outlet for the flow of fiber suspension therethrough, and a filter screen divides the container into an upstream compartment and a downstream compartment. Each compartment has an electrode pair disposed therein, each electrode pair including a cylindrical outer electrode configured for flow of fiber suspension therethrough and an inner electrode. Each electrode pair is connected to a differential amplifier, with the differential amplifiers connected to a microprocessor.

Abstract: The circuit of the present invention is able to detect and identify the position of several contactors.Each contactor (1) is mounted in series with a resistor (2). The first contacts (A.sub.N) are interconnected. The same applies for the second contacts (B.sub.N) and the third points (C.sub.N) of the branches established. In addition, the third points (C.sub.N) are separated by a second resistor (6). The measuring of the voltage between the first and third points (A, C) makes it possible to detect and identify the open and closed contactors and in addition is able to detect a malfunction.Application for detecting the position of the doors of a thrust reverser of a turbojet engine.

Abstract: There is disclosed a surge discriminating and locating system having at least one master station and at least one slave station. The system comprises surge receiving means for receiving surges which occur on a power transmission line, locating means for locating a point where the surge occurs, digitizing means for digitizing said surge into a digital signal, extraction means for extracting from said digital signal the characterized portions thereof as information representative of the surge waveform, memory means for storing predetermined reference information concerning the nature of surges, and discriminating means for comparing said information representative of the surge wave form with said reference information stored in said memory means to discriminate the kind of surge.

Abstract: A method is specified for detecting ground faults on the conductors of electrical machines, in which method the fault resistance (Rf) is directly calculated in a numerical evaluation unit (7) from the injected (Ui) and the measured (URE) voltages. Since the fault resistance is explicitly calculated and displayed, it is independent of influences from the ground reactance. Moreover, there is no need to, for each machine, characteristics for drawing conclusions on the fault resistance. Moreover, the influence of ageing, temperature fluctuations, injection level fluctuations etc. is eliminated due to the numerical calculation. (FIG.

Abstract: A process for determining a surface resistance to microwave energy of a superconductive film provides a metallic cavity resonator whose resonator cavity is defined by metallic walls, and positioning a superconductive film whose microwave surface resistance is to be measured as at least part of a wall of the cavity. A dielectric body is applied to a surface of the film and microwave energy is coupled to the cavity through an input antenna and microwave energy is coupled out of the cavity by an output antenna at which signals are produced as a measure of the microwave surface resistance of the film.

Abstract: The present invention concerns a measuring device, notably for measuring the level of glucose in blood, intended to be used with a removable sensor comprising at least one active zone. In particular, the invention concerns the electrical connection between the measuring device and the removable sensor. Each electrical contact surface of the removable sensor is connected to two electrical contact organs to enable the condition of the electrical contacts between these electrical contact organs and the corresponding contact surfaces to be checked before a measurement is carried out.

Abstract: An apparatus for automated polyelectrolyte measurement in process materials comprises a sample vessel with an outer wall defining a cylindrical cavity and with a reservoir of larger diameter above and in communication with the cavity. A liner for the cavity and the reservoir are made of an electrically insulating material such as polytetrafluoroethylene. To clean the apparatus there is also provided an ultrasonic oscillator which is mechanically coupled to the sample vessel. In order to improve the cleaning process, the liner and preferably also the reservoir are attached to the outer wall in such a way as to resist tensile and shear forces and the ultrasonic oscillator is attached to the outer wall. Preferably, the liner is attached to the outer wall by an adhesive.

Abstract: In order to measure the amplitude and the phase of the reflection coefficient of a structure (S) such as a radar protection radome, particularly following a repair, a measuring device is proposed, whereof a portable part (10) makes it possible to transform the microwave measuring and reference signals into low frequency signals. These low frequency signals are then transferred by flexible cables (16, 17) to a calculating part (12, 14) without it being possible to create phase distortions by twisting of the cable. The signals are transformed by giving the portable part, in addition to the main microwave generator (18), a second microwave generator (32), whose frequency (f.sub.2) differs from that (f.sub.1) of the main generator by a given low frequency (f.sub.0). Microwave mixers (38, 42) use the radiation emitted by the second generator (32) in order to give the measuring signal and the reference signal, initially at the frequency (f.sub.1), the low frequency (f.sub.0).

Abstract: The apparatus comprises a plurality of connectors (9, 10, 11, 12 . . .) for connecting to the component to be tested (e.g. a transformer), a signal generator (19), a measuring system (23) and control means (22) which is arranged to control which of the connectors (9, 10, 11, 12 . . .) are connected to the signal generator (19) and the measuring system {23) and arranged to control the function of the signal generator (19) and the measuring system (23) so that the same signal generator (19) and measuring system (23) can be used to carry out a variety of different tests on the component, the signal generator (19) also being arranged to provide a synchronising signal (28) to the measuring system (23) so that the phase relationship between measurements at different times can be calculated by comparing the phase relationships of those measurements with the synchronising signal (28).

Abstract: The present invention relates to a device for the vector measurement of ultra-high frequency signals of the same angular frequency of the six port junction type, comprising a power divider (10) and a phase shifting circuit (11) two of the six ports of said device being measuring ports connectable to two sources of signals to be characterized, the four other ports being connected to four detectors, one of them being a matched detector (14) and the three others (12, 13, 15) being unmatched detectors.