Abstract: A constant current loop measuring system is provided for measuring a characteristic of an environment. The system comprises a first impedance positionable in the environment, a second impedance coupled in series with said first impedance and a parasitic impedance electrically coupled to the first and second impedances. A current generating device, electrically coupled in series with the first and second impedances, provides a constant current through the first and second impedances to produce first and second voltages across the first and second impedances, respectively, and a parasitic voltage across the parasitic impedance. A high impedance voltage measuring device measures a voltage difference between the first and second voltages independent of the parasitic voltage to produce a characteristic voltage representative of the characteristic of the environment.

Abstract: A megohm tester for determining resistance utilizing a relaxation oscillator which generates output pulses, at a rate dependent on an unknown resistance detected at a test site within an electronic apparatus, which can then be compared to known values provided as standards.

Abstract: A method for measuring the resistance or conductivity between two or more conductors which are placed against a semiconductor element, wherein in order to bring the contact resistance between the conductors and the element to, to hold it at,a predetermined value during measuring, the conductors are held at a constant distance and/or under constant pressure relative to the semiconductor element.

Abstract: An apparatus for providing a quantitative measurement of high frequency corona discharges from electrical devices operating at high voltages, including an alternating current power source for providing a test signal variable in amplitude and frequency, a high pass filter to reject power source cyclical components and to isolate corona discharge components, an adjustable gain amplifier, and a power meter providing a quantitative readout of the amplitude of corona discharges integrated over a preselected time period. Electromagnetic shielding of individual assemblies comprising the test equipment allows corona detection without emissions or interference from external sources.

Abstract: A hand held wand utilizes an elongated rigid hollow longitudinally extending stainless steel tube open at both ends. A data collection probe is disposed in one tube end. A data uploading port is disposed in the other tube end. The probe and port each include a stainless steel body electrically and mechanically engaging the tube. Each body has a front surface disposed outside of the tube with a peripheral annular ring and a central recess extending inwardly and terminating in a rear surface having a first opening. Each body also includes a corresponding longitudinally extending central electrode disposed in the corresponding recess. Each central electrode has an exposed front surface flush with the ring and a rear surface aligned with and spaced from the opening. Electrical insulation is disposed in the recess to electrically isolate the electrode from the body and the tube. The two bodies and the tube define a common external electrical ground with respect to the central electrodes.

Abstract: A system for detecting arcing faults in DC electrical cable power distribution circuits, typically in telecommunications networks, monitors the power spectrum of distribution lines over a frequency band of about 4 Hz to 5 KHz in which current surges characteristic of arcing line faults have been found to occur. The system compares power levels in this detection band with a threshold level typical of normal communications traffic and registers an alarm condition when an excess indicative of arcing is detected.

Abstract: A battery detect circuit (32) is connected to the battery with the current input to the battery and extracted from the battery measured with a sense resistor (50) and then converted to charge and discharge pulses with a V/F converter (52). A microcontroller (64) is operable to increment a Nominal Available Charge (NAC) register (180) during a charge operation, and to increment a Discharge Count Register (DCR) (184) during a discharge operation. The NAC register (180) indicates the available charge, which value is output to a display (34). The maximum value to which the NAC value can rise is limited by a value stored in the last measured discharge register (182). This value represents the value stored in the DCR (184) whenever the battery is discharged from an apparent full state to a fully discharged state. This results in a qualified transfer to the LMD register (182) such that no knowledge of the actual battery charge is necessary.

Abstract: The invention relates to a method and a device for detecting a flashover between conductors in power transmission lines of different voltage levels suspended from the same towers and wherein the power lines are included in a power network where one of the power lines is stated to be a high-voltage power line (1) and where the other power lines are connected to the high-voltage line via transformers of a known transformer ratio (am) and internal impedance (ZXm) and wherein the line impedances (ZL) are known. Specific to the invention is that the fault current which is caused by a flashover is set to be equal to a detected current change in any of the phases in the high-voltage line. With this assumption an equation system can be set up with the aid of which the relative distance to fault n (0<n<1) can be determined. If the produced value of n lies within the stated region, this is interpreted as if an internal flashover has occurred.

Abstract: Portable and disposable apparatus for leak testing surgical and/or examination gloves which may be worn on the body of the user to permit convenient detection of glove leaks during diagnostic procedures. In one embodiment there is provided an electrolyte-containing pouch worn on the body of the user and into which gloved hands may be inserted for evaluation. A leak in a glove permits the electrolyte to penetrate the glove and contact the skin of the wearer to close an electrical circuit and trigger an alarm.

Abstract: An integrated circuit including a comparator having two output states and being responsive to a voltage developed across a shunt in the circuit so that the comparator assumes one of its two output states when the voltage developed across the shunt is greater than a threshold switching voltage and the other of its two output states when the voltage developed across the shunt is less than the threshold switching voltage. The integrated circuit additionally includes a threshold switching voltage sensitivity control circuit, coupled to and controlling the comparator, for controlling a sensitivity of the threshold switching voltage to changes in a supply voltage of the lamp circuit and for controlling a sensitivity of the threshold switching voltage to changes in temperature of the integrated circuit.

Abstract: A system for measuring a broad range of impedance values with high precision and over a broad frequency band. Both the broadrange impedance measurement capability of the V-I method and the broadband frequency measuring capability of the reflection coefficient method are provided. A remote measurement capability is also available. Based upon the V-I method, a selection is made between a circuit to achieve an ideal open and a circuit to achieve an ideal short circuit in response to the impedance values. A boundary for selecting the impedance is, for instance, 50.OMEGA.. To measure a high impedance, the ideal open type circuit is selected; to measure a low impedance, the ideal short circuit is selected. The source and measuring instruments are extended by a coaxial cable. A floating measuring instrument is obtained by using a balun. Impedance measurements for 1 MHz to 2 GHz are possible.

Abstract: In an improved electromagnetic induction-type conductivity meter utilizing primary and secondary transformer coils about a liquid sample passageway, a resistance circuit having a conductive lead line extending also through the coils and parallel with the sample passageway is provided. The resistance circuit can be selectively opened and closed, and has the capacity to contribute to the measurement voltage detected on the detector coil when the primary coil is excited. The value of this additional resistance voltage can be used for calibration and monitoring the condition of the conductivity meter.

Abstract: Monitoring apparatus is provided for the ignition system of an internal combustion engine such as is provided in a motor vehicle, which is capable of detecting a variety of malfunctions of ignition under a variety of engine operating ranges, so that the catalyst used in the exhaust system of the engine can be protected by setting lambda=0 and/or cutting off fuel injection to an inoperative cylinder, in as many instances of malfunction as possible. Various methods of monitoring are available and are correlated for selection in accordance with the different operating ranges of the engine. The ignition spark duration and the ignition discharge voltage are measured for individual sparks on the primary side of an ignition coil and are compared with limit values for correct ignition, these limit values being selected from a memory in accordance with the particular range of operating conditions in which the engine is operating.

Abstract: A device for providing a signal emulating the wetness of plant leaves, includes a first generally horizontal surface; a second, generally upwardly facing sloped surface having an edge spaced above the first surface by a gap, so that drops of moisture can accumulate on the second surface, and run off the edge, bridging the gap, and first and second leads extending from the first and second surfaces, respectively, to measure the conductivity/resistivity across the gap. Also disclosed is a method of providing a signal emulating the wetness of plant leaves including the steps of: providing a first generally horizontal surface; providing a second, generally upwardly facing sloped surface having an edge spaced above the first surface by a gap, so that drops of moisture can accumulate on the second surface, and run off the edge, bridging the gap between the first and second surfaces; and measuring the conductivity/resistivity across the gap between the first and second surfaces.

Abstract: An electrical test buzzer is adapted for insertion into an output receptacle and used to test for the presence of electricity at the output receptacle. The electrical test buzzer includes an audible alarm, a transformer, held in a housing, and a pair of contact prongs. The contact prongs are inserted into a respective output receptacle causing the buzzer to sound a high pitched alarm when electricity is present at the receptacle. When no electricity is present at the receptacle no circuit is formed and the alarm does not sound.

Abstract: A sensor for monitoring the water content and the acid content in the presence of water in nonaqueous media can be incorporated into a monitoring system for monitoring the quality of nonaqueous fluids in equipment or vehicles. The sensor comprises an insulating substrate; electrodes formed on the substrate in an interdigitated pattern; and a conductive polymer deposited over the interdigitated electrodes which bridges between adjacent digits of the electrodes. The monitoring system incorporating the sensor comprises a control module for measuring the conductivity of the sensor. The control module is preprogrammed to compare the measured conductivity to a predetermined level indicative of an unacceptable level of degradation. The sensor is made by depositing electrodes on an insulating substrate; depositing a conductive polymer over the electrodes in an amount sufficient to bridge between the electrodes; and neutralizing the conductive polymer to an insulating form.

Abstract: An apparatus and method for the measurement of, for example, the moisture in a material or, more generally, for the measurement of any material parameter which may be inferred by measuring the electromagnetic properties of the material under investigation. The meter apparatus comprises a controllable source of electromagnetic energy having stable selectable frequency. The controllable source of electromagnetic energy is coupled to a material measurement chamber by means of probes, loops, antennas, apertures or other structures so as to establish an electromagnetic field inside the measurement chamber thereby causing the field to interact with the material contained in the chamber. The method includes passing the process material through a frequency sensitive measurement cell. Exposing the process material to electromagnetic energy produced by a multi-frequency source. Generating an output signal having a distinctive frequency response characteristic.

Abstract: The relay includes means for obtaining current and voltage samples on the power transmission line for a particular possible fault type. The current sample is multiplied by the replica impedance of the power transmission line, while the voltage sample is multiplied by a polarizing voltage to provide a first complex expression having a real portion and an imaginary portion. The product of the current sample and the replica impedance is multiplied by the polarizing voltage to produce a second complex expression having a real portion and an imaginary portion. The real portion of the first complex expression is then divided by the real portion of the second complex expression to produce a scale value m which is compared against known reference scale values for each zone, so as to determine underimpedance conditions in any one of the zones.

Abstract: An apparatus is adapted to detect the linear extension, velocity and acceleration of a hydraulic cylinder. The hydraulic cylinder defines a variable length coaxial resonant cavity Under the control of a controller, an RF transmitting section and an RF receiving section are used to determine the resonant frequency of the cavity. The receiving section includes a comparator circuit for increasing the sensor's sensitivity and eliminating spurious detections of the cylinder's resonant frequency. The linear extension of the cylinder is determined as a function of the resonant frequency.

Abstract: A sample is loaded along with a carrier gas into a column. The column discharge is introduced into a chamber downstream of spaced electrodes which create a pulsed DC spark. The spark produces a spectral emission and a metastable carrier gas dispersion that then reacts with molecules of the sample to bring the sample to an excited state. The excess energy surrendered by the sample is characteristic of the species and can be measured by detector electrodes in the chamber.