Abstract: A differential voltage monitor is shown using a resistive bridge to produce a sample value representing that differential voltage. A portion of the resistive bridge is located on an IC and a portion is external to the IC. The object is to compare the differential voltage with a reference, producing a logic signal at a threshold level. The threshold level serving as a reference and the sample valve representing the differential voltage are made to be equally dependent on the bridge components located on the IC. In this way, any changes in the IC located bridge resistors compared to the bridge resistors located outside the IC are prevented from affecting the measurement.

Abstract: A device for testing pairs of wires in a cable which includes a testing console having known means for performing tests on the wires and having a test fixture with a plurality of pins extending through a mating surface, the pins being arranged and arrayed to enter holes containing wires to by tested in a terminal fixture, the terminal fixture having holes into which wires may be inserted and held by friction, the holes opening in a terminal fixture having the holes in the same array as the array of pins in the test fixture so that when the terminal fixture and the test fixture are brought together with the same orientation the pins extending from the test fixture enter the holes in the terminal fixture and make a circuit between the testing console and the wire, and the console includes a rotating switch arrangement to bring both ends of each wire into circuit with testing equipment consecutively and one-at-a-time.

Abstract: An electrical outlet wiring analyzer includes generator circuitry for periodically providing an alternating current pulse of one cycle at a frequency of an alternating current voltage supplied by an electrical outlet having a plurality of conductors. The wiring analyzer also includes connecting circuitry for electrically applying the alternating current pulse to at least one of the conductors and circuitry for determining an impedance of each of the conductors to which the alternating current pulse is applied. Another embodiment of the electrical outlet wiring analyzer includes pulser means for periodically providing a current pulse of one-half cycle at a frequency of an alternating current voltage supplied by an electrical outlet having a plurality of conductors.

Abstract: An oil deterioration detector comprising a sensitive electrode whose electric potential varies in response to acidity and/or basicity of oil to be measured, and a reference electrode associated with this sensitive electrode. An electrically conductive housing accommodates the sensitive electrode and the reference electrode together with the oil. A potential difference detector detects oil deterioration by measuring a potential difference between the sensitive electrode and the reference electrode. And, an insulating member is interposed between these electrodes and the electrically conductive housing for electrically insulating these electrodes from the electrically conductive housing. The reference electrode is grounded together with the electrically conductive housing. An insulating, hydrophilic porous member would be interposed between the sensitive electrode and the reference electrode.

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: In one aspect of the present invention, an apparatus detects a shorted winding condition of a solenoid coil. The apparatus includes a reference solenoid that is connected to a test solenoid. A sine generator drives the reference solenoid with a sinusoidal waveform to cause an induced voltage across the test solenoid. A meter determines the voltage difference between the solenoids and compares the voltage difference to a predetermined value.

Abstract: A faulted circuit indicator with a high visibility spherical display device is disclosed for indicating a fault condition disposed within the display apparatus is a permanent magnet 42 that is in magnetic communication with, and actuated by, an electromagnet. The permanent magnet is rotatably mounted within the display and is attached to a spherical flag. The spherical flag has two different colors at its hemisphere to represent fault and no-fault conditions. The electromagnet comprises a magnetic core and coil assembly and is magnetized by a current pulse received from the indicator circuitry. By changing the direction of the current through the coil assembly, the polarity of the electromagnet is reversed, which in turn causes the permanent magnet to rotate 180.degree. to realign with the poles of the electromagnet. Because the flag is colored about its hemisphere, the rotation of the permanent magnet results in a change of color being displayed in the display device.

Abstract: Disclosed are a method and apparatus for real time process monitoring of thermoplastic filament winding. During processing, the thermoplastic filament winding is wound around an electrically conductive mandrel. An electrically conductive roller, juxtaposed and movable radially with respect to the mandrel, is provided for compression of the portion of the thermoplastic filament disposed on the mandrel. Accordingly, a dielectric capacitor is formed between the mandrel and the roller with the portion of the thermoplastic disposed between the mandrel and roller acting as the dielectric of the capacitor. An input voltage is applied to the dielectric capacitor, and the permittivity and loss factor of the capacitor are determined by monitoring the input voltage and output current to thereby determine the degree to which the thermoplastic has consolidated.

Abstract: An apparatus and method for measuring electrical parameters of a medium such as electrical conductivity and dielectric constant between a pair of electrodes are disclosed. The medium can be a liquid, gas, powder, etc., and the electrodes can be coaxial metallic circular cylinders. To compute electrical conductivity, the device is immersed in the medium to an immersion depth and the conductance across the electrodes is determined. The measurement is repeated at at least one additional immersion depth. By obtaining a differential conductance measurement with respect to the immersion depth, the effects of fringe conductances are eliminated from the measurement. The device can also be used to determine dielectric constant of the material by obtaining a differential capacitance measurement with respect to immersion depth. The device need not be calibrated by performing resistance measurements in a known standard solution.

Abstract: A method and apparatus for determining whether semiconductor components are electrically connected to a printed circuit board. A voltage (or current) is connected to two traces leading to connections to a semiconductor component to be tested. The initial current (or voltage) is measured at an initial temperature. Then, the temperature of the semiconductor is changed. Current (or voltage) is measured again after the temperature change. A change in current (or voltage) indicates that the semiconductor component is electrically connected to the trace.

Abstract: A potentiometry apparatus for measuring a periodic electrical waveform existing proximate the surface of a sample such as a semiconductor wafer is disclosed herein. The potentiometry apparatus includes a pulse generator for generating a sequence of electrical pulses at a pulse frequency offset from the frequency of the surface waveform by a mixing frequency. A cantilever coupled to the pulse generator serves to carry the electrical pulses to a position proximate the surface of the sample. In a capacitive displacement mode the cantilever is mechanically displaced so as to generate a time-expanded representation of the electrical surface waveform having a repetition frequency equal to the mixing frequency. During displacement mode operation an optical detection circuit may be employed to monitor deflection of the cantilever. In a tunneling current mode the cantilever is again employed to carry the electrical pulses to a position proximate the surface of the sample.

Abstract: A ground fault interrupter 10 includes a core 12. Two load current-carrying wires 14, 16 pass through the core 12. A primary coil 44 is carried on the core 12 for sensing a current imbalance in the wires 14, 16. An auxiliary coil 18 is wound on the core 12. A pair of back-to-back zener diodes 20 is connected in series with the coil 18 to supply current to the coil 18 when an applied voltage exceeds a predetermined value between wires 14 and 16 or between either one of the and ground.

Abstract: A test system for testing propagation delays of outputs of integrated circuit devices. The test system includes a test circuit for applying input signals to selected inputs of the digital integrated circuit and for sampling selected outputs of the digital integrated circuit, and respective loads for each of the selected outputs, each load having an impedance that is configured such that the sum of the specified internal delay for such output and a load dependent delay for such output comprise a total propagation delay that is substantially identical for all of the selected outputs, whereby all of the selected outputs are sampled simultaneously.

Abstract: An insulating condition detecting apparatus for a wire-cut electrical discharge machine in which insulation between a wire electrode and a workpiece is detected without rising any other special power source than a power source for machining. A voltage between the wire electrode (6) and the workpiece (6) is detected during a period. A switching element (3) for electrical discharge, formed of a semicondctor, is turned off and a switching element for charging is turned on to charge the capacitor. When the detected voltage is lower than a reference value, it is determined that the insulation between the wire electrode and the workpiece is unsatisfactory, and a dielectric breakdown signal is outputted.

Abstract: A new method for analyzing an electrical waveform of the type portrayed on a graph includes the steps of selecting a waveform to be analyzed, establishing the boundary of a window-like area and generating a signal if the waveform is in a predetermined position with respect to the area. For example, a signal such as a failure signal is generated if the waveform is to be out of the area but, in fact, is in the area. The method also includes features for determining certain parameters, e.g., rise time, period and the like, for the waveform. The steps include selecting first and second points on the waveform and determining the time lapsed between points. Details regarding the structure of a new waveform analyzer are also disclosed.

Abstract: The output of a bridge measurement circuit is sampled at a time when there is no desired, or expected, bridge output signal, and a balance voltage applied to the bridge measurement circuit is automatically adjusted such that the sample bridge output signal is equivalent to a reference output signal. After the bridge is balanced, the balance voltage is automatically modified by a calibration voltage calculated to provide a known change in the sample bridge output signal, and the sample bridge output signal is compared to a reference output to automatically check the bridge measurement circuit gain. The balance voltage may be automatically modified by multiple calibration voltages, and the sample bridge output signal provides an indication of the linearity of the amplifier gain. The sample bridge output signal is monitored after a change in the balance voltage to automatically provide an indication of the bridge measurement circuit filter cutoff frequency.

Abstract: A ground detecting method for an inverter unit and an apparatus for carrying the method into practice and which zero-phase current is detected on the basis of the output current from the inverter unit. A first value is added whenever the zero-phase current exceeds the ground level. When the added value reaches a predetermined value, it is judged as being the ground level. Further, when the zero-phase current is smaller than the ground level, a second value smaller than the first value, which is added whenever the zero-phase current exceeds the ground level, is subtracted from the added value.

Abstract: The present invention provides a transient event detector for use in a nonintrusive electrical load monitoring system at a monitored site having at least one electrical load. The transient event detector includes a data acquisition portion for acquiring and storing start-up power transient pattern data associated with each electrical load being monitored; a monitor for continuously monitoring total power load pattern data at the site; and a processor for correlating the transient pattern data to the total power load pattern data in order to identify each electrical load.

Abstract: A method and apparatus for detecting faults in digital, analog, and hybrid integrated circuits is disclosed. A single test vector employing bias voltage on input used in conjunction with pulsing the power supply rails is used to allow detection of the various faults which may be present. The instantaneous rail current (i.sub.DD) is then employed for analysis of the circuit, preferably by neural network.

Abstract: A low intrinsic capacitance probe system for measuring capacitance to detect the liquid fill level of a pressure vessel that incorporates a high pressure center rod retention system and an explosionproof flame path seal into its mounting gland. The system reduces or eliminates the cold flow of PTFE within the probe and eliminates the need for periodic retorquing.