Abstract: A method is disclosed for processing, optimization, calibration, and display of measured dielectrometry signals. A property estimator is coupled by way of instrumentation to an electrode structure and translates sensed electromagnetic responses into estimates of one or more preselected properties or dimensions of the material, such as dielectric permittivity and ohmic conductivity, layer thickness, or other physical properties that affect dielectric properties, or presence of other lossy dielectric or metallic objects. A dielectrometry sensor is disclosed which can be connected in various ways to have different effective penetration depths of electric fields but with all configurations having the same air-gap, fluid gap, or shim lift-off height, thereby greatly improving the performance of the property estimators by decreasing the number of unknowns.

Abstract: Method and apparatus for controlling amplifier gain, e.g., as used in ESV of a xerographic copier, has a light source, e.g., an LED, optically coupled to a gain control light dependent resistor (LDR). The LDR can be in a negative feedback loop around an amplifier. There is a voltage sensing probe located near the photoreceptor belt of the copier and coupled to an input of the amplifier.

Abstract: The present invention relates to an electronic circuit and an array of such circuits for precisely measuring small amounts or small changes in the amount of charge, voltage, or electrical currents. One embodiment of the present invention provides an electronic circuit for measuring current or charge that can be used with a variety of sensing media (including high impedance sensing media) that produce a signal by either charge or current production or induction in response to physical phenomena occurring within the sensing media. In another embodiment, the voltage level (bias) of either the sensing or reference electrode can be switched relative to the other upon receipt of a triggering pulse. This changes the polarity of the electric field to cause charge of the opposite polarity to be driven to the sensing electrode, thereby eliminating the need to electrically connect a discharge path to the sensing electrode to clear the charge accumulated at the sensing electrode.

Abstract: The design of Shaded Rotor devices to demonstrate the existence of a hypothetical Universal Particle Flux Field is presented. These devices should extract a measurable amount of energy from this Field. We believe the Universal Particle Flux Field can explain all invisible forces at a distance phenomena between masses, charged bodies, and magnetic materials. We propose that the Universal Particle Flux Field is a simultaneously convergent/divergent field, where the particle streams traverse to any point in the Universe from every other point in the Universe. The order of this Flux Field is a nearly perfect disorder, which is an order in itself. The strength of the gravitational component of this Field is conventionally denoted by “G”. Two neutral masses immersed in such Flux Field will develop forces between them, which are consistent with Newton's Equation of Gravitation. This Field is also consistent with Electrostatic, and Magnetic Force Equations.

Abstract: Particles in a fluid cause an arc at a certain electric field whose value depends on the nature of the particles (size, composition, and the like). By applying an electric field across the fluid and determining the value of the electric field at which the arc occurs, the nature of the particles can be determined. For example, if their composition is known, their size can be determined, and vice versa. The device for carrying out such testing has a first electrode with an interior opening and a second electrode having a pin through the interior opening to define a passageway for the fluid. The electric field is varied, either by varying a voltage applied between the electrodes or by forming the passageway to be tapered. Multiple such passageways can be provided, as by forming the first electrode from honeycomb-expanded metal, thus reducing pressure drop, energy consumption without decreasing sensitivity to low concentrations.

Abstract: An electric potential sensor includes a piezoelectric tuning fork provided with a vibrating body of tuning fork type, a driving piezoelectric element provided on a first arm of said vibrating body, and a feedback piezoelectric element provided on a second arm of the vibrating body. A detection electrode is provided on the piezoelectric tuning fork. A signal-processing circuit, which is connected to the detection electrode, detects changes in the electric signal generated in said detection electrode which are attributable to the quantity of charge on the surface of an object to be measured. A self-oscillation circuit has an input end of which is connected to the feedback piezoelectric element and an output end of which is connected to the driving piezoelectric element. A gain control circuit is provided on the self-oscillation circuit. A comparator includes an input end which is connected to the feedback piezoelectric element and an output end which is connected to said gain control circuit.

Abstract: A method and apparatus for measuring a charge on a surface, such as on a semiconductor wafer, arising during plasma processing is provided. Such a charge may be measured on an insulating film applied to such a wafer. By the present invention, the charge on such an insulator exposed to plasma is measured in-situ using micro-cantilevers. The micro-cantilevers include an insulating base positioned on the substrate and a cantilevered beam extending therefrom to over the substrate. The beam is formed of a conductive material. A charge on the beam causes an opposite charge to form on the substrate. The opposite charges attract to move or deflect the beam towards the substrate. The amount of movement or deflection corresponds to the magnitude of the charge. This movement or deflection of the beam can be measured to determine the charge by bouncing a light source, such as a laser, off of the beam. In another embodiment, the cantilever includes a flexible bridge interconnected between the base and a rigid beam.

Abstract: An electric potential sensor, having: a power source including a first output terminal having a first electric potential, a second output terminal having a second electric potential; a first and a second potential dividing elements connected in series between the first output terminal and the second output terminal; a ground node connected to a mutual connection node of the first potential dividing element and the second potential dividing element; a first resistance element connected between the ground node and an output node; a second resistance element connected between the output node and a detection node; a transistor connected between the first output terminal and the detection node; a pickup device for controlling a base current or a gate voltage of said transistor such that an electric potential of the detection node is equal to an electric potential of a measuring object; and a third resistance element connected between said detection node and the second output terminal.

Abstract: This invention relates to a system and method for economically locating an ESD event with a reasonable degree of accuracy. It performs this function using a binary approach in which one or more binary ESD locator boxes are used. Each of these binary ESD locator boxes incorporates two antennas and performs the function of determining which of these antennas receives the ESD signal first. This determination establishes the ESD event as occurring to one side of a planar surface. By incorporating one or more additional binary ESD locator boxes, the system can determine whether an ESD event occurred within a two dimensional area or within a three dimensional area.

Abstract: A contactless process for detecting electrical patterns on the outer surface of a member comprising providing a member having a charge pattern on an outer surface, repetitively measuring the charge pattern on the outer surface of the member with an electrostatic voltmeter probe maintained at a substantially constant distance from the surface, the distance between the probe and the imaging member being slightly greater than the minimum distance at which Paschen breakdown will occur to form a parallel plate capacitor with a gas between the probe and the surface, the frequency of repetition being selected to cause all time dependent signals to fall out of phase by a predetermined amount, and averaging the out of phase time dependent signals over a sufficient number of measuring repetitions to eliminate the time dependent signals. In one embodiment, the contactless process detects surface potential charge patterns in an electrostatographic imaging member.

Abstract: A wearable device for alerting a user when a static electrical charge has developed on the user which exceeds a preset limit, prior to an accidental discharge of the static charge. The device includes a first conductive element in close proximity to the user and a second conductive element spaced a further distance from the user than the first conductive element. A high impedance differential amplifier provides a voltage signal proportional to the potential difference existing between the first and second conductive elements. A voltage level discriminator receives the voltage signal from the high impedance differential amplifier and triggers an alarm if the voltage signal exceeds a predetermined limit.

Abstract: A device is described which combines Acoustic and Electroacoustic spectrometers to characterize both particle size distribution and zeta potential for concentrated dispersed systems.The Acoustic Spectrometer measures both attenuation and sound speed for multiple frequencies using each measurement to help optimize and correct the other. The attenuation spectra is used to calculate particle size.The Electroacoustic Spectrometer measures Colloid Vibration Current (CVI), correcting the measured value using attenuation and sound speed data from the Acoustic Spectrometer. The Colloid Vibration Current is used to calculate zeta potential taking into account the particle size calculated from the acoustic measurement as well as particle interaction.Sound speed and multiple frequency CVI measurement provide additional experimental data to check the validity of the data.

Abstract: A measuring apparatus has a capacitor incorporated in a handy measuring tool electrically connected to a voltage meter, and a sharp leading end of the capacitor is brought into contact with a lead of a large scale integrated circuit device for accumulating movable electric charge induced in the presence of a charged insulating package into the capacitor so that the amount of the accumulated movable electric charge is calculated from a potential difference produced between electrodes of the capacitor.

Abstract: A composition of matter utilizes an exact dielectric replicate matching reference material to make a detection device component that triggers and maximizes a dielectrokinesis (phoresis) phenomena (force, torque, energy replenishment), which can be used to detect the presence of specific entities of a predetermined type that contain as a major component the matching dielectric material. Different designs and materials of construction for the detection device component enable the detection of a variety of specific entities including human beings, animals, plastics, metals, water, etc. Detectors using the component can detect the present of a specific entity irrespective of the presence or absence of any type of intervening, visual obstructing material structures or barriers, lighting conditions, weather conditions or electromagnetic interference (EMI).

Abstract: A measuring apparatus has a capacitor incorporated in a handy measuring tool electrically connected to a voltage meter, and a sharp leading end of the capacitor is brought into contact with a lead of a large scale integrated circuit device for accumulating movable electric charge induced in the presence of a charged insulating package into the capacitor so that the amount of the accumulated movable electric charge is calculated from a potential difference produced between electrodes of the capacitor.

Abstract: A method and a measuring system for detecting static electricity in a measuring object includes at least a sensor, a voltage meter, and a processor unit with a signal processing unit connected to the voltage meter. The sensor includes a sensing element arranged so that the electric field of the measuring object induces in the sensing element an electric signal which is proportional to the change in the electric charge of the measuring object. The sensor includes a detector including a capacitive circuit, such as a capacitor circuit, having an integrating effect on the measuring values which are read off by the voltage meter, connected between the sensing element and the voltage meter.

Abstract: In a surface potential sensing device, a sense electrode electrically independent of an object is located at a preselected distance from the object for sensing the surface potential of the object Electrostatic capacitance between the object and the sense electrode is varied in order to detect two or more variables in a potential signal output from the sense electrode. The potential detection signal is corrected on the basis of the two or more variables.

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 contactless process for detecting surface potential charge patterns in an electrophotographic imaging member including at least one photoconductive imaging layer having an imaging surface, providing a scanner including a capacitive probe having an outer shield electrode, maintaining the probe adjacent to and spaced from the imaging surface to form a parallel plate capacitor with a gas between the probe and the imaging surface, providing a probe amplifier optically coupled to the probe, establishing relative movement between the probe and the imaging surface, maintaining a substantially constant distance between the probe and the imaging surface, applying a constant voltage charge to the imaging surface prior to relative movement of the probe and the imaging surface past each other, synchronously biasing the probe to within about .+-.

Abstract: A surface potential sensor which is less affected by noise superposed on a reference source voltage than prior sensors, and hence can improve measurement accuracy with ease, and which also has higher stability against extraneous noise. The sensor includes an initial-stage input circuit comprising an FET, and a succeeding-stage amplifier circuit mainly comprising an operational amplifier for amplifying a difference between an AC component from the initial-stage input circuit and a reference source voltage. A resistor is connected between a drain of the FET constituting the initial-stage input circuit and a source voltage line to take out a signal from the FET drain. The source voltage supplied to the FET is the reference source voltage.

Abstract: In a surface potential measuring apparatus for measuring a potential configuration by moving a photosensitive body of an image forming apparatus of electrophotographic type and at least one potential sensor relative to each other and by generating dielectric current in the potential sensor due to change in potential on a surface of the photosensitive body and by analyzing the dielectric current, a width of a detecting portion of the potential sensor is smaller than a width of the change in potential to be measured, and a sectional shape of the detecting portion in a plane perpendicular to the surface of the photosensitive body and parallel to the relative movement direction does not include any edge.

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 electrometer probe is used in an electrophotographic apparatus as part of a process control system to measure charge on a photoconductive film belt. This measurement is used to control voltage level or other process parameter of the electrophotographic process. The probe is supported in an electrometer probe holder so that a sensor aperture of the probe is at a fixed distance from the film belt. In order to ensure proper operation of the electrometer probe, a method and an apparatus for independently calibrating the electrometer probe is provided. A curved plate is provided on the electrometer probe holder. The plate is mounted at the same spacing from the probe aperture as the film belt. This plate has a receptacle for the service person's test lead to attach. The other end of the test lead is attached to a test point for the toning station bias supply. The probe may be reoriented on the probe holder to position the probe aperture at the fixed distance to the plate.

Abstract: Determining the location of an ESD event is achieved through the use of an envelope detector or absolute value comparator which identifies the arrival of an electromagnetic waveform generated by an ESD event at each of a plurality of antennas. Arrival times are compared to determine the location of the ESD event. A plurality of N antennas are employed, and each antenna is coupled to a corresponding envelope detector, threshold discriminator, switch, and register. The output of a clock is coupled to the switches, and a microprocessor is coupled to the registers. When an antenna receives a waveform corresponding to ESD, the envelope detector extracts an envelope signal related to the envelope of the waveform and couples the envelope signal to the threshold discriminator. When the envelope signal has a value above a specified threshold, the threshold discriminator sends a signal to latch the current count of the clock into the corresponding register.

Abstract: A testing apparatus including a testing plate can be used to test an electrostatic wafer chuck. A DC potential is supplied so as to produce an electrostatic force. A mechanical force is supplied to the testing plate in order to give an indication of the produced electrostatic force. By examining the DC potential and the produced electrostatic force, an electrostatic wafer chuck can be qualified or rejected before being placed into a wafer processing machine. This reduces the possibility of damage to the wafer or the wafer processing machine.

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: A cryogenic apparatus for microscopy of physical properties of an object including a thin, stiff, transparent substrate or window within the outer wall of the vacuum space of a dewar and a cryogenic sensor within the vacuum space and spaced very close distances to the window. This construction allows for positioning a sample for measurement outside of the vacuum space, at room temperature or higher and for microscopy of physical properties of the sample by monitoring the output from the cryogenic sensor as it is scanned along the surface of the sample.

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: Improved electronic circuitry incorporated into a tag attached to a user worn wrist strap of a static electrical discharge dissipation system. The electronic circuitry monitors the electrical connection of the wrist strap from the user to ground and tests the functionality of the tag. The electronic circuitry comprises an oscillator, a signal transmitter, a discharge resistor and a discharge resistor check circuit for monitoring the accuracy of the discharge resistor. The electronic circuitry also comprises a skin resistance check circuit for monitoring the electrical connection of the wrist strap to the user, and a ground fault detect circuit for monitoring the electrical connection of the wrist strap to ground.

Abstract: Apparatus and method are presented for supplying electrostatic discharges to a device under test. A discharge probe is employed for applying the discharges to the device. The probe is moved to preselected position points relative to the device during the test. The probe is displaced from one preselected position point to the next in response to position control signals supplied by a controller. The controller includes a memory for storing address data respecting the preselected position points.

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: The dielectrophoretic force caused by the non-uniform electric field squared spatial gradient three-dimensional pattern uniquely exhibited by a predetermined type of entity can be detected by locator device. A human operator holds the device in hand to thereby electrically connect to the human operator. The human operator's naturally occurring very low electrical decay time constant is increased through electronic circuitry externally connected to the device. The device is held in a balanced horizontal state, and the operator scans the device in a constant uniform motion back and forth. An antenna extends from the front of the device, and both are acted on by the dielectrophoretic force. This force results in a subsequent resulting torque, acceleration, vibration or any other measurable quantifiable manifestation of the force about the handle's pivot line hence driving the device and its antenna toward the direction and position of any entities of the predetermined type that are within range.

Abstract: An electrometer that is able to measure the potential difference of an electrostatically charged body without causing a rapid discharge of the subject charge. The electrometer has an input impedance that is in excess of 100 gigohms. The input impedance is created by an active voltage divider. The active voltage divider is a unique circuit which instead of the typical voltage divider that utilizes a passive resistive divider and an op amp in a voltage follower configuration, uses an amplifier configuration that attenuates its input signal. One result of this configuration is that the input line can then be guarded. This allows the device to be supplied with probes that are not subject to typical elements of degradation of the input signal with distance from the circuit, e.g. parasitic capacitance and bandwidth limitations.

Abstract: A sensor installable within a gas turbine engine for sensing electrostatic charge therein. The sensor comprises a sensing plate and first and second shielding plates. The sensing plate has a first face with a first peripheral portion, and a second face with a second peripheral portion. The first and second shielding plates are spaced from and positioned relative to the first and second faces of the sensing plate, respectively, by a layer of electrically insulating material, so that electrostatic charge in the proximity of the sensor is sensed by both the first and second peripheral portions of the sensing plate.

Abstract: A contacting electrostatic voltmeter suitable for sampling positive or negative potentials on an electrostatically charged surface. The electrostatic voltmeter includes a selectively controllable actuation mechanism that enables the use of a contacting electrostatic voltmeter to sample the surface of an electrostatically charged member, moving relative thereto, within a predetermined space. The invention finds particular use in a printing system, where it enables charge monitoring during printing yet avoids disturbance to charged latent image areas on the imaging member.

Abstract: A method and device is disclosed for determining the distribution of charge and size in a colloidal system. The arrangement disclosed is adapted to measure these characteristics in an inhomogeneous colloid. A colloid is subjected to a steady or slowly varying force which moves the particles at a rate that depends on their radius or charge and thereby sets up spatial inhomogeneities in the suspension, and to either a unsteady mechanical force or an unsteady electrical force, and the resulting electrical or acoustic effects sensed. Monitoring these characteristics over time and subsequent calculation allows the determination of charge and size distribution, for each species present.

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: A voltage monitor which uses the shift in absorption edge of crystalline material to measure strain resulting from electric field-induced deformation of piezoelectric or electrostrictive material, providing a simple and accurate means for measuring voltage applied either by direct contact with the crystalline material or by subjecting the material to an electric field.

Abstract: This electrostatic selector of aerosol particles of an atmosphere has a first (18) and a second (20) parallel, spaced, coaxial conductive disks, between which is established an electric field, an annular slot (22) made in the first disk for communicating with the atmosphere to be examined, a central intake (26) for bringing about a circulation from the periphery of the disks of a stable, centripetal, laminar filtered air flow, an annular or circular opening (28) made in the second disk, a third disk (32) facing the second disk, means for injecting between the second and third disk, from the periphery thereof, a radial, laminar, filtered air flow, a central pipe fixed to the third disk by which the particles having the requisite electrical mobility (or the requisite dimension if the electric charge is known) are brought to the outside of the apparatus.

Abstract: The present invention is a device for measuring the electric surface charge density on each surface of a sheet. The sheet can either be moving or non-moving. If the sheet is non-moving a pliers-like device having a pair of electrodes aligned opposite with each other is used. The sheet is placed between the electrodes and the surface measurement is made by either one or two electrometers. For a moving web, the apparatus includes a first and second roller each having a charge measurement segment electrically isolated from the roller shell wherein the charge measurement segments periodically engage the web running through the two rollers. Two grounded shields which periodically shield the charge measurement segment are provided. Two electrometers are provided and from this surface charge density measurement and net charge density measurement on the moving sheet are obtained.

Abstract: A number wheel assembly (10) for a counter mechanism has a plurality of number wheels (13-18), each number wheel (13-18) having a sleeve (48) around its circumference with a plurality of positions representing successive increments in a count, a substrate (26-31) opposite one surface of the number wheel (13-18), the substrate (26-31) carrying an electrode (42) that is spaced from the number wheel (13-18) to form an air gap for a variable capacitor, and wherein the number wheel (13-18) carries at least one dielectric element (46) that is rotated with the number wheel (13-18) to vary the capacitance of the variable capacitor according to the position of the number wheel (13-18). Circuitry for detecting the capacitance and the position of the number wheels (13-18) is provided on a circuit board (39) that is electrically connected to the number wheels (13-18).

Abstract: An electrostatic actuator incorporates a sensor for detecting both position and the state of distribution of charges and is efficiently driven in high-speed operation. A first member has a plurality of driving electrodes thereon, each having the shape of a strip, a second member is placed in contact with the first member, and a control means is provided for changing the voltages applied to the driving electrodes to produce relative movement of the first member and the second member. Detecting electrodes are arranged on the first member at predetermined phases, independently of the driving electrodes, and a detecting unit detects the position of the second member and the state of charges induced on the second member, through the detection of electric signals induced in the detecting electrodes by the charges distributed on the second member.

Abstract: The invention is an electrostatic coalescer testing apparatus for testing the ability of chemical additives to facilitate electrostatic coalescence of water in a water hydrocarbon-containing mixture.

Abstract: A circuit tracer for determinating the location of a conductor, such as a wire, which is either an open or closed circuit, and which may lie underground. The tracer includes a transmitter which is connected to the conductor, a hand-held probe, and a receiver which is connected to the probe. The probe has three different sensors: an electric field sensor, primarily for locating the terminus of an open-ended conductor or for distinguishing such a wire in a bundled cable of wires; a differential electric field sensor, for determining the direction to and location of an open-ended conductor located above ground; and an inductive sensor for determining the direction to and location of a current-carrying conductor, including an open-ended conductor lying below ground. A switch selectively provides the output from one of the sensors to the receiver unit, which determines the magnitude of any signal based upon the direction the probe is pointing.

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: The orientation of a polarized capacitor is determined by applying a voltage signal to one of the leads of the capacitor and a reference signal to the other lead. The magnitude of the electric field thus generated by the capacitor is measured. Then the voltage signal and the reference signal are reversed. The magnitude of the new electric field thus generated by the capacitor is measured. The ratio of the magnitudes of the first measured electric field to the second measured electric field is computed. If the ratio is greater than one, then the capacitor is determined to be properly oriented. If the ratio is less than one, then the capacitor is determined to be improperly oriented.

Abstract: An electrostatic voltmeter suitable for use in a non-contacting, positive or negative potential sensing, type electrostatic voltmeter. The invention enables a flexible, low cost electrostatic voltmeter to be produced using high-voltage field-effect transistors in the circuit design. The invention further includes input conditioning components that enable high-voltage sensing and high-voltage feedback in such a manner that processing of the input signal from the sensor is accomplished without producing a variation in the current passing through the field-effect transistor in response to voltage variations. Elimination of this variation further reduces the susceptibility of the remaining signal processing circuitry to transient direct current signals. A differential cascode as the input stage is the preferred configuration for the input conditioning components.