Abstract: A lightning detection system for detecting and locating an initial discharge of an initial leader stroke of a lightning flash. An initial lightning discharge produces a pulse that can be used to accurately detect lightning, and more particularly, the location of the initial lightning discharge. In one embodiment, at least three sensors detect and determine the location of the first pulses from initial lightning discharges using time difference of arrival information of the pulses at each of the three sensors. In another embodiment, a single sensor is used to determine the range of an initial lightning discharge from the amplitude of a corresponding initial detected pulse, and to determine the direction from a crossed loop antenna An alternative embodiment of a single sensor system determines a distance of a lightning event from a peak amplitude value derived from a pulse amplitude distribution.

Abstract: A field sensor (1) comprising means for measuring a magnetic field and an electric field, wherein at least six capacitor plates (5, 6, 7, 15, 16, 17, 25, 26, 27, 35, 36, 37)are provided which are arranged in a cube and in that in the space thus formed the means for measuring the magnetic field is provided, which means is three-dimensionally aligned and for example consists of coils (2, 3, 4), Hall-effect sensors, magnetoresistors or the like.

Abstract: An apparatus and method for measuring the transfer impedance of a structure. Oscillator driver 20 produces a small electrical drive signal into structure 40. Field probe 30 detects the electric field produced by the drive signal and is comprised of a skinny half-dipole and fat half-dipole antenna. Fat half-dipole 34 encloses synchronous detection circuitry. Power supplies are isolated for all components. Base station 10 communicates with oscillator driver 20 and field probe 30 via wireless links 92 and 44 to control the drive signal, the synchronous detection, and to determine the transfer impedance.

Abstract: An apparatus and method of detecting, tracking and displaying lightning activity is disclosed. A lightning stroke has associated therewith electric and magnetic field components characterized by maximum rise times and minimum power levels. The field signals comprise a plurality of sub pulses also. An electric field antenna and a pair of magnetic field antennas are disposed to receive the field components associated with lightning activity. Control circuitry cooperating with rise time and threshold measuring which operates on the field signals received by antennas generates control signals including integration and sampling control signals over a predetermined time interval (preferable one point four seconds) and for sampling and holding the field signals at each of the sub pulse peak. Preprocessing circuitry upon command from a programmable microprocessor A to D converts the sampled field components where they are stored as digital data in memories.

Abstract: A new method is introduced to characterize EMC at the IC/ASIC package level. It is designed to excite the modes of radiations found in IC/ASIC packages, and permits the characterization of packages in a way that represents their real application. In the new method, a small antenna designed on a die is mounted inside the package under test. The package is mounted on a carrier PCB that is used to feed a signal into the antenna on the die. Radiated emissions from this set-up are measured. The antenna on the die is measured in free space to obtain a reference level which represents its capability to radiate without shielding. The antenna is then measured inside a package to obtain its capability to radiate with package shielding. The difference between the two measurements will represent the shielding effectiveness or the EMI reduction the package offers to the die. All measurements may conveniently be performed inside a TEM (Transverse Electromagnetic Mode) cell.

Abstract: According to one embodiment of the present invention, a voltage probe for measuring common-mode (CM) voltage of a device under test (DUT) having differential input/output (I/O) signals is disclosed. The probe includes a connector adapted to couple to the DUT, at least one output measurement port configured to connect to a measuring device for measuring the CM voltage, and at least one differential pair cable connected to a connector and to a at least one measurement port for coupling a differential I/O signals to a measurement port. According to a second embodiment, the present invention provides a voltage probe for measuring CM voltage of a DUT having differential I/O signals while the DUT is simultaneously connected to an auxiliary equipment. According to a third embodiment, the present invention provides a method for measuring EMI from a DUT. A CM voltage probe is interposed between the DUT and an EMI measurement device. The CM voltage is measured at an measurement port of the voltage probe.

Abstract: An evaluation system and retest method uses essential coupling physics of lightning, monitored system geometries, and on-line sensor readings for generating and comparing monitored retest indices to critical retest indices using a retest chain algorithm using pre-launch analyses to then provide real-time retest decisions for spacecraft launch operations following major lightning storms.

Abstract: A reusable miniaturized detector that utilizes magneto-optic elements to detect the occurrence of an electrostatic discharge during the manufacture or handling of electrostatic discharge sensitive electronic components and circuit boards. The device may also be used to determine the polarity and magnitude of the electrostatic discharge. The device may be manually or automatically read, either by removing the device from the environment being monitored or continuously monitoring in situ. The device can also be configured to provide protection to some electrostatic discharge events which could damage sensitive components being monitored.

Abstract: The subject matter of the present invention is a fiber-optic outdoor high-voltage sensor 1. The known sensor principle is based on the fact that a piezoelectric quartz cylinder 3 wound with a glass fiber 4a effects a voltage-proportional fiber strain which is measured interferometrically. According to the invention, a 420 kV outdoor sensor 1 is created by virtue of the fact that several quartz cylinders 3 and electrically conductive spacing elements 5 are arranged in an alternating fashion one behind another and are sealed in a silicone-shielded 17 insulating tube 16 by means of polyurethane 18 or silicone 21. Dividing the high voltage between several spaced, E-field integrating sensor elements 2 permits simple field control and a very high measuring accuracy. In addition, the fiber-optic voltage sensor 1 is distinguished by a low outlay on insulation, compactness and low weight, and can easily be scaled to other voltage levels and be effectively combined with optical current sensors 38.

Abstract: A method and an apparatus for providing non-contact measurement of waveforms proximate to a surface of a sample. In one embodiment, the described apparatus includes a composite probe waveform generator configured to provide a composite probe waveform having a plurality of overlapping component probe waveforms. Each of the overlapping component probe waveforms have a repetition rate substantially equal to the repetition rate of the sample waveform to be measured from the sample. The apparatus includes a cantilever with a signal path to carry the composite probe waveform to a position above the sample surface where the sample waveform is to be measured. In one embodiment, each of the component probe waveforms of the composite probe waveform is modulated at a frequency near a mechanical resonance frequency of the cantilever.

Abstract: A radiation measurement system includes a dipole antenna (4,18) for radiating an EM field in response to an electrical signal generated by an opto-electrical converter (12). The opto-electrical converter (12) is provided with an optical signal representing the EM field to be emitted. Optical signals avoid disturbance of the EM field by a coaxial cable required to feed the antenna. In order to obtain an ideal dipole antenna with well known radiation properties, an inner conductor (16) is used to couple the signal from the opto-electrical converter (12) to both halves (4,18) of a hollow dipole antenna. FIG.

Abstract: A method of detecting precursor seismic electromagnetic waveforms and predicting future seismic activity in the form of an earthquake by placing a detector including a dielectric material in contact with the earth. The detector receives at the dielectric material precursor seismic electromagnetic waveforms traveling within the earth emanating from a region of seismic activity. A sensor responsive to the dielectric material senses a series of individual discrete signals imposed by the waveforms at the dielectric material wherein each of the signals has the characteristic of a rise time that is shorter than its fall time. Alternatively, the discrete signals may be a single discrete signal characterized by a plurality of overlapping waveforms. Then predicting based on the series of the signals the occurrence of the earthquake.

Abstract: Particulates are trapped by laser beam and brought into contact with electrodes to electrochemically and spectroscopically measure the reaction process thereof.Precise measurement of the process of chemical reactions such as electrochemical and photochemical ones of a single particulate is made possible.

Abstract: An electric field measurement system for precisely measuring low frequency electric fields includes a capacitive antenna having two parallel conductive plates (11, 12). The potential between the plates is a measure of the electric field present. A high impedance element (13) supplies the potential between the plates to an electro-optical converter (14) which converts the potential into an optical signal. The optical signal is coupled into an optical fiber (20) which transports the optical system to an optical-electrical converter (30), where the optical signal is converted into an electric signal, which is measured by a measurement device (31), e.g. a spectrum analyzer. The use of an optical fiber avoids disturbances of the field to be measured. The dimensions of the plates of the capacitive antenna, preferably, are only a few centimeters, thereby minimizing the influence of the antenna on the field to be measured.

Abstract: A diastrophism detection method and an apparatus therefor are provided which is capable of predicting a position of occurrence of diastrophism such as an earthquake or the like, a scale thereof, time thereof and the like with increased accuracy without being affected by various artificial and natural noises and being effectively put to practice utilizing a simple and objective judgment procedure and by means of equipments simplified in structure and reduced in cost. A VHF radio wave beyond a line-of-sight distance through a plasma density distribution abnormality zone temporarily formed in the ionosphere during diastrophism such as an earthquake or the like is detected in the form of abnormal propagation, resulting in a position of diastrophism below the plasma density distribution abnormality zone, a scale thereof, time thereof and the like being judged.

Abstract: A non-contact probe provides information as to relative amplitudes of harmonics of a current or voltage waveform as well as total harmonic distortion. The probe includes a non-contact sensor with an amplifier coupled thereto. Output signals from the amplifier are digitized and analyzed in a programmed processor. Output from the processor provides a display of relative harmonic amplitudes as well as an indicator of total harmonic distortion.

Abstract: A current detector and metering circuit is provided for a dielectrokinesis detecting device. This device is particularly useful in the areas of locating obscured entities, such as human beings, animals, materials, or controlled substances. A current detector is attached to an antenna and detects when subtle changes in the dielectrokinesis occurs within an detection environment. The present current detector automatically zeros itself to ambient electric field values and then has a heightened sensitivity for changes in that electrical field caused by changes in the dielectrokinesis. The present invention can be used for detection of hidden entities or substance, for motion detection, for medical diagnostic detection, and other uses.

Abstract: A magnetic field sensor which can be used as an active antenna is disclosed that is capable of small size, ultrawideband operation, and high efficiency. The sensor includes a multiplicity of magnetic field transducers, e.g., superconducting quantum interference devices (SQUIDs) or Mach-Zehnder modulators, that are electrically coupled in a serial array. Dummy SQUIDs may be used about the perimeter of the SQUID array, and electrically coupled to the active SQUIDs for eliminating edge effects that otherwise would occur because of the currents that flow within the SQUIDs. Either a magnetic flux transformer which collects the magnetic flux and distributes the flux to the transducers or a feedback assembly (bias circuit) or both may be used for increasing the sensitivity and linear dynamic range of the antenna.

Abstract: A magnetic field sensor which can be used as an active antenna is disclosed that is capable of small size, ultrawideband operation, and high efficiency. The sensor includes a multiplicity of magnetic field transducers, e.g., superconducting quantum interference devices (SQUIDs) or Mach-Zehnder modulators, that are electrically coupled in a serial array. Dummy SQUIDs may be used about the perimeter of the SQUID array, and electrically coupled to the active SQUIDs for eliminating edge effects that otherwise would occur because of the currents that flow within the SQUIDs. Either a magnetic flux transformer which collects the magnetic flux and distributes the flux to the transducers or a feedback assembly (bias circuit) or both may be used for increasing the sensitivity and linear dynamic range of the antenna.

Abstract: Apparatus and methodology for detection of lightning. The invention includes an antenna and amplifier for receiving the electrostatic and/or electromagnetic discharges of lightning and electrical noise and outputs an analog electrical signal representative of the discharge. The analog signal is applied to a threshold detection circuitry whose output is activated when the input signal rises above a predetermined level. The output of the threshold circuitry is a series of pulses of varying length. A computer or other programmable device is connected to the output of the threshold circuitry and opens an event window when the first pulse is received and determines the number of pulses received and the total duration of the pulses during the event window. The number and total duration of the pulses is compared to stored pulse signatures of lightning discharges and man made electrical noise.

Abstract: An electric discharge machine for machining a workpiece by an electric discharge by supplying a machining fluid to a gap between an electrode and the workpiece and supplying pulses to the workpiece while providing the electrode with a jump motion, said jump motion being a periodic motion of the electrode relative to the workpiece; wherein said electric discharge machine detects a state quantity caused in a main body of the electric discharge machine by a reactive force produced by a machining operation in the gap between the electrode and the workpiece and changes machining conditions of the workpiece in accordance with a detected value of the state quantity.

Abstract: A lightning detection system implemented via a modem or a soundcard is described. The modem is either internally or externally coupled to a communication or computer device. The modem uses one of the unused wires present in the four wire telephone cord that plugs into the modem as an antenna. A digital signal processor (DSP) internal to the modem is configured to function as an AM detector wherein the received signals are processed for determination of a potentially damaging lightning storm. The modem generates an interrupt request based upon the results of the DSP. The interrupt request notifies the communication or computer device which in turn is programmed via a software application to notify the user, such as displaying a warning message on a display device or in initiating a power down sequence.

Abstract: A method and an apparatus for providing non-contact measurement of waveforms proximate to a surface of a sample. In one version, the describe apparatus includes a probe waveform generator that generates probe waveforms with the same repetition rate as a sample waveform to the measured from the sample. The apparatus includes a cantilever with a signal path to carry the probe waveform to a position above the sample surface where the sample waveform is to be measured. The apparatus of the present invention also includes a gate to periodically route the probe waveforms to the cantilever tip. The gate is controlled by a periodic gating signal with a period substantially longer than the signal period of the sample waveform. In one version, the gate is switched at a repetition rate substantially equal to a mechanical resonant repetition rate of the cantilever. Capacitive coupling between the cantilever and the signal line of the sample results in a periodic motion of the cantilever at the gating repetition rate.

Abstract: Method and apparatus of measuring a critical current value of a superconducting wire formed by wire sections S(n), n being 1.ltoreq.n.ltoreq.N and initially set to 1, comprising a first step (a) of determining electric currents I(m), m being 1.ltoreq.m.ltoreq.M; a second step (b) of setting m to 1; a third step (c) of passing the electric current I(m) through the wire section S(n); a fourth step (d) of detecting a voltage generated in the wire section S(n) by the electric current I(m); a fifth step (e) of replacing m with m+1; a sixth step (f) of repeating the steps (c) to (e) until m is equal to M; a seventh step (g) of replacing n with n+1; an eighth step (h) of repeating the steps (b)-(g) until n is equal to N, thereby obtaining N.times.

Abstract: A magnetic field sensor which can be used as an active antenna is disclosed that is capable of small size, ultrawideband operation, and high efficiency. The sensor includes a multiplicity of magnetic field transducers, e.g., superconducting quantum interference devices (SQUIDs) or Mach-Zehnder modulators, that are electrically coupled in a serial array. Dummy SQUIDs may be used about the perimeter of the SQUID array, and electrically coupled to the active SQUIDs for eliminating edge effects that otherwise would occur because of the currents that flow within the SQUIDs. Either a magnetic flux transformer which collects the magnetic flux and distributes the flux to the transducers or a feedback assembly (bias circuit) or both may be used for increasing the sensitivity and linear dynamic range of the antenna.

Abstract: The invention relates to a method of monitoring anti-lightning protection equipment that includes a grounding line (1), the method being characterized in that a "lightning" electrical current travelling along the grounding line is measured. The measurement may be obtained, in particular, by means of a magnetic circuit (2) constituting a closed loop around the grounding line, and electrical circuit that includes a winding (5) disposed around the magnetic circuit so that a lightning current travelling along the grounding line induces current in said winding, the magnetic circuit including a core (3) of solid magnetic material that has at least one gap in the magnetic circuit, said gap being occupied by material that is not magnetic.

Abstract: The invention relates to an apparatus and method for detecting electrical charge with a long integration time and in particular to a sampling method which reduces noise that affects the accuracy of the measurement of the total charge. The apparatus samples the charge on the capacitor at the start of the integration period to obtain a sample proportional to a first noise component. It then samples the charge on the capacitor at the end of an integration period and subtracts the noise component sample from the integrated charge sample to obtain a measure of integrated charge to the relative exclusion of the noise component. The circuit uses a folded cascode amplifier and at least one correlated double sampling circuit. The charge detector can be used with any apparatus which generates electrical charge in response to an input including for example, a photodetector, photomultiplier, ion detector, e beam detector and piezoelectric charge detector and arrays of such devices.

Abstract: A dielectrokinesis detector includes a chamber housing an exact dielectric replicate reference material that is subjected to external static electrification. The reference material is mechanically constrained, enabling the detection of the polarization energy dynamics of constrained dielectrophoretic force indicating the presence of any target with dielectric properties identical to the properties of the reference material. An antenna assembly increases the proximity distance (range) of detection. The static electrification source for the reference material increases the longevity of the detection ability to provide continuous detection capability, and an external electronic circuit source of electrical energy via an electrical current surge gives a quantifiable manifestation of the detection.

Abstract: Detection of the existence, magnitude, and frequency of occurrence of a plurality of ESD events is achieved by using an envelope detector to process signals generated by ESD events and received by an antenna. The ESD event detector includes an antenna for producing a signal waveform in response to electromagnetic fields incident thereupon, a demodulator coupled to the antenna for generating an envelope waveform that is related to the envelope of the signal waveform, a threshold window discriminator coupled to the demodulator for generating an indication signal if the envelope detected by the demodulator has a magnitude between a first and a second threshold, and a counter coupled to the threshold window discriminator for counting the number of indication signals received from the threshold window detector.

Abstract: This invention relates to an electrostatic field measuring device which incorporates the phenomena of floating electrodes. The invention has no moving parts and is based on the use of the discharge frequency of floating electrodes as a measure of electric field intensity.

Abstract: A handheld fieldmeter is implemented with an automatic function to drive the voltage on an output node of signal processing circuitry to circuit ground while a sensing electrode is disposed in a static-free environment. In response to a binary signal indicating whether the output node voltage is above or below ground, a microprocessor repeatedly increments/decrements a stored auto-zero multibit number, and generates successive PWM pulse streams of differing duty cycles determined by the incremented/decremented auto-zero number. The successive PWM pulse streams are integrated to ultimately produce fine zero adjustment current used by the signal processing circuitry to drive the output node voltage essentially to circuit ground. The fieldmeter also includes a pair of LEDs relatively positioned with the sensing electrode to emit light beams that intersect at the surface of a charged object when the sensing electrode is positioned a prescribed distance from the charged object.

Abstract: A magnetic field sensor which can be used as an active antenna is disclosed that is capable of small size, ultrawideband operation, and high efficiency. The sensor includes a multiplicity of magnetic field transducers, e.g., superconducting quantum interference devices (SQUIDs) or Mach-Zehnder modulators, that are electrically coupled in a serial array. Dummy SQUIDs may be used about the perimeter of the SQUID array, and electrically coupled to the active SQUIDs for eliminating edge effects that otherwise would occur because of the currents that flow within the SQUIDs. Either a magnetic flux transformer which collects the magnetic flux and distributes the flux to the transducers or a feedback assembly (bias circuit) or both may be used for increasing the sensitivity and linear dynamic range of the antenna.

Abstract: An apparatus for measuring the vertical component of the gradient of the electrical field of the soil surface includes two electrodes. Each electrode includes a capacitor with a semiconductor layer.

Abstract: A device and a method for locating partial discharges in dynamoelectric high-voltage machines and/or high-voltage systems, comprising at least two coupling units (16, 17, 18) which are coupled to mutually spaced measuring points (MP1, MP2, MP3, ES, TS, AKV) of a conductor (2) of the high-voltage machine and/or high-voltage system, and couple out a high-frequency electromagnetic signal produced upon the occurence of partial discharges. The device further comprises an evaluation device which is electrically connected to each coupling unit (16, 17, 18) and records the temporal sequence of the signals coupled out by each coupling unit (16, 17, 18). The place of origin of the partial discharges can be determined from the temporal sequence of the signals, it being possible to enhance the accuracy by additional measurements at further measuring points.

Abstract: An ESD sensor includes a plurality of layers of dielectric material positioned on a substrate, each having a different thickness, a first contact positioned adjacent each of the plurality of layers and a plurality of second contacts, one each positioned on each layer of the plurality of layers of dielectric material. Each different thickness of each individual layer of dielectric material is formed to provide a specific voltage at which an electrical short will occur between the first and second contacts when an ESD appears thereacross, so that the sensor provides an indication of a range of voltages.

Abstract: An apparatus and a method for predicting an earthquake are disclosed. The apparatus employs a set of two electrodes for measuring the vertical component of the gradient of the electrical field due to the capillary movement and the surface evaporation of the ground water, a humidity sensor for measuring the humidity of the soil surface, and a temperature sensor for measuring the temperature of the soil surface. The correlation coefficient between the changes in the electrical field gradient due to changes in the surface temperature related to the water evaporation from the soil surface is calculated. The correlation coefficient changes its sign at the time of appearance of the earthquake precursor.

Abstract: An apparatus for detecting and measuring disturbances in an electromagnetic field caused by the electrostatic potential of a charged object moving the field includes a DC source, a loop/solenoid coil, and a metering unit. The DC source charges the loop/solenoid coil, and thereby creates the electromagnetic field that emanates from the coil. The metering unit is provided to (indirectly) sense and quantify the disturbances in the electromagnetic field of the loop/solenoid coil by indicating a change in a current flow through the coil. The apparatus may be configured with a housing to enclose a plurality of components of the apparatus including the DC source, the loop/solenoid coil, and the metering unit.

Abstract: A sensor device and method for finding the location of a conductor such as a wire, having an alternating voltage and which is not readily visible, i.e. hidden in the wall of a structure or buried. The detector device has four plates in two balanced pairs and arranged in a quadrilateral with a central reference plate. This reference plate provides a common mode rejection of the background electric field typically present for instance on the wall, which is induced by the alternating voltage in the wire. A sharp signal peak is detectable immediately over the wire from a differential signal of a pair of the balanced plates, when the plates of the pair are located on either side of the wire. Also a determination based on the sum and difference of the signals from the two plates allows one to determine the relative phase induced in the two plates of each pair, which indicates the direction in which the sensor device should be moved in order for the plates to be immediately over the target wire.

Abstract: A lightning detection system for detecting and locating an initial discharge of an initial leader stroke of a lightning flash. An initial lightning discharge produces a pulse that can be used to accurately detect lightning, and more particularly, the location of the initial lightning discharge. In one embodiment, at least three sensors detect and determine the location of the first pulses from initial lightning discharges using time difference of arrival information of the pulses at each of the three sensors. In another embodiment, a single sensor is used to determine the range of an initial lightning discharge from the amplitude of a corresponding initial detected pulse, and to determine its direction from a crossed loop antenna. An alternative embodiment of a single sensor system determines a distance of a lightning event from a peak amplitude value derived from a pulse amplitude distribution.

Abstract: An infrasonic frequency resonant circuit and method for use thereof. An electric power distribution system is employed both as antenna for ISF signals and as a source of inductive reactance for a resonant circuit tuned to a band within the ISF spectrum. A capacitor is placed from the neutral conductor to the ground conductor at an ac power outlet in a structure to form a resonant circuit ordinarily tuned to a band within the ISF spectrum. An ISF spectrum analyzer is connected to the neutral and ground terminals of the resonant circuit to visualize ISF electromagnetic signals induced on the electric power distribution system in both the frequency domain and the time domain and so as to be more readily evaluated.

Abstract: A method of detecting precursor seismic electromagnetic waveforms and predicting future seismic activity in the form of an earthquake by placing a detector including a dielectric material in contact with the earth. The detector receives at the dielectric material precursor seismic electromagnetic waveforms traveling within the earth emanating from a region of seismic activity. A sensor responsive to the dielectric material senses a series of individual discrete signals imposed by the waveforms at the dielectric material wherein each of the signals has the characteristic of a rise time that is shorter than its fall time. Alternatively, the discrete signals may be a single discrete signal characterized by a plurality of overlapping waveforms. Then predicting based on the series of the signals the occurrence of the earthquake.

Abstract: A power line fault locating system employing combinations of conducted electrical transient signals recorded at specific points in the power delivery network, radiated electromagnetic signals produced by the air-gap arc preceeding the fault current or by the lightning discharge causing the fault, and knowledge of the power line path associated therewith. The arrival time of conducted transient signals produced by the fault are detected with microsecond accuracy through use of a fault recording sensor (FRS). The low level electromagnetic radiation (VHF/UHF) caused by arcing associated with power line faults is detected at at least one arc detection sensor (ADS) located at some distance from the power line. The ADS senses the time of arrival of the radiated signal associated with the fault.

Abstract: A combination and unitary corrosion monitor and reference cell for cathodic protection systems includes an elongated tubular metal element of the same material as the structure to be protected and a reference cell on one end of the tubular element, adapted to be buried or submerged in an electrolyte. The tubular element includes resistance connections along its length and a reference resistance element sealed inside. Ratiometric resistance measurements enable the extent of corrosion and corrosion rates to be determined with automatic compensation for temperature changes. Both the resistance measurements and the potential measurements from the cell may be taken from the same test station or location.

Abstract: A process is disclosed for ascertaining the microdefect levels of an electrophotographic imaging member comprising the steps of measuring either the differential increase in charge over and above the capacitive value or measuring reduction in voltage below the capacitive value of a known imaging member and of a virgin imaging member and comparing differential increase in charge over and above the capacitive value or the reduction in voltage below the capacitive value of the known imaging member and of the virgin imaging member.

Abstract: During voltammetric analysis of liquids, the indicator electrode must be frequently changed in order to prevent memory effects and resultant changes to basic conditions during measurement. In order to be able to change the indicator electrodes simply, a plurality of indicator electrodes are arranged on a common carrier. For accommodation of the liquid (2) to be analysed, a vessel (1) is provided and the carrier (5) is mounted to move in relation to this vessel (1) in such a way that one of the indicator electrodes (6) can be selectively brought into the area intended for the liquid. The reference electrode (8) necessary for the measurement is arranged in the vessel (1) and likewise connected with the measuring device (20). With that, changing of the selected electrode (6) ensues by moving the carrier (5) relative to said vessel (1).

Abstract: A method of detecting failed disks in power-system surge arresters comprising a network of at least two parallel-coupled stacks of series-coupled ZnO varistors includes measuring differential current flow through each pair of stacks during surge voltage conditions, and comparing the current so measured with a fixed fraction of the total current carried by the arrester. Because each stack contains a like number of substantially identical varistors, current flow through the stack containing a failed disk will measurably exceed current flow through each non-defective stack. If the measured current flow through a stack is excessive relative to current flow through the remaining stacks, the excessive current flow stack is presumed to contain a defective disk. In today's technology, precision Rogowski coils or fiber-optic current sensors provide the high-bandwidth, high dynamic-range transducers necessary for the measurement of both total and differential current.

Abstract: A method an apparatus for detecting icing on an aircraft particularly flight surfaces by using the electrical insulating properties of ice on a conductive wing surface utilizing a simple conductive current device engageable selectively on the suspect flight surfaces.

Abstract: Surface potential is detected with high precision by removing induction noise generated by a drive circuit and transmitted to a detection electrode. Induction noise imparted by a drive circuit to an A.C. voltage signal is cancelled out by supplying an output of a pre-amplifier for amplifying the A.C. voltage signal derived from a detection electrode and an output of the drive circuit for applying a drive signal to a chopper portion to a differential amplifier and differentially amplifying them. Particularly, an attenuator for making a level of the amplified A.C. voltage signal substantially coincident with a level of a signal from the drive circuit and an inverter/amplifier for making phase deviation coincident are provided in an output portion of the pre-amplifier circuit.

Abstract: The current density versus voltage characteristics of integrated circuit processing equipment such as a plasma etcher are determined using a passive probe including a semiconductor wafer in which one or more clusters of individual passive charge monitors are fabricated. Each monitor includes an EEPROM device having a control electrode and a floating electrode over a channel region connecting source and drain regions, a charge collecting electrode connected to the control electrode, and a current sensing resistor connecting the charge collection electrode to the substrate for developing a threshold varying voltage. By determining changes in device threshold voltage, a corresponding surface-substrate potential is determined which can be divided by the value of the current-sensing resistor to yield a current. The current can then be divided by the area of the charge collecting electrode to yield a value of the current density.

Abstract: The performance of a device under test is observed with and without the presence of controlled EMI fields. Voltage signals from the device under test are transmitted to an oscilloscope by overdamped conductors, a hybrid electrical/optical transmitter, a fiber optic cable, a receiver and a conductor cable. The overdamped conductors are transparent to the EMI fields and the current in those conductors is kept very small by the use of a very high input impedance in the transmitter. The hybrid transmitter may be an analog or a digital transmitter.