Abstract: In a system for measuring a surface potential of a sample, a probe is located above. A surface of the sample with a small gap and is vibrated by a piezoelectronic element which is energized by a oscillator. A potential of the distal end of the probe is changed and is converted into an electrical signal. The surface potential is obtained from the electrical signal.

Abstract: A method of making a calibrated measurement of the contact potential difference between a probe electrode and the surface of a sample surface involves the use of a reference standard. The reference standard comprises an electrolyte solution in electrical contact with an electrochemical half-cell; the surface of the electrolyte constitutes the reference surface whose CPD can be measured. The method is intended for use with apparatuses such as a vibrating capacitor or Kelvin probe, and allows the absolute work function of a sample surface to be determined from measurements obtained in a gas atmosphere. An apparatus incorporating the reference standard, and an improved vibrating capacitor probe, are also disclosed.

Abstract: Disclosed is a multi-channel electrostatic sensor apparatus including a main oscillation circuit; a plurality of pull-in type sub-oscillation circuits which are adapted to synchronize with the main oscillation circuit to generate sub-frequency signals whose frequency is equal to the main oscillation frequency or a multiple thereof; and a plurality of resonance circuits which are sensitive to any change in exterior capacitance when detected by an associated detector for changing its resonator resonance point with respect to the sub-frequency signal. Positive synchronization of the sub-oscillation circuits with the single main oscillation circuit prevents any adverse effect from being caused by the varying stray capacitance in flexible conductors connecting the sub-oscillation circuits to the main oscillation circuit while allowing the relatively free movement of the video heads of a video system, on which video heads the sub-oscillation circuits and subsequent components are attached.

Abstract: An apparatus and method for generating microscopic scan data of C-V and/or dC/dV over a scan area. A scanning microscope, for example a scanning force microscope, is provided with a voltage biased tip, for example, of tungsten, which is scanned across an area to derive the data. The data can be used to derive a plot of semiconductor dopant level across the scan area. Other material properties can be derived, for example, carrier generation and recombination rates and subsurface defects.

Abstract: The invention is an instrument for determining the work functions (unbiased) or absolute surface potentials (biased) of conducting sample surfaces. These values are inferred from measured surface potential differences between the sample and the instrument's non-contacting sensor. Charge incurred in the sensor by the proximity and surface potential of the sample surface alters the impedance of a semiconductor channel within the sensor. The deviation in the charge dependent impedance of the sensor from a calibrated zero-field reference is used by a feedback controller to alter the base potential of the sensor to eliminate the deviation signal. In this state, the surface potential of the sensor matches that of the sample thus forming a zero-field condition, as a result no charge is induced in the sensor. The surface potential difference between the sample and the sensor is then equal to the sensor base voltage, which is directly measured by a voltmeter.

Abstract: A non-contacting electrostatic voltage follower comprising a detector electrode sensitive to electrostatic quantities such as electrostatic fields, voltages, charges and the like, a modular coupled to the electrode for modulating the capacitance coupling between the electrode and a surface bearing an electrostatic quantity to which the electrode is exposed, a detector amplifier of the current summing type having the summing input thereof connected to the detector electrode, and a high bandwidth amplifier having an input connected to the output of the detector amplifier. A probe comprises a transparent carrier element coupled to the modulator, a first conductive and transparent film on a surface of the carrier and defining the detector electrode, and a second film of conductive and transparent material on the remainder of the surface of the carrier and spaced from the first film.

Abstract: A surface potential detecting apparatus includes an electro-optical crystal element (22), wherein an electric field from a surface to be measured is directly or indirectly applied to a measuring electrode (24) of the electro-optical crystal element, and an alternating voltage which is obtained by stepping up an oscillating voltage generated in an oscillating circuit (35) is applied to a reference electrode (25) of the element from a step up circuit (34). Light which passes through the electro-optical crystal element is received by a photosensitive unit (30). Zero electric field is detected (31) based on the output of the photo sensitive unit, and a trigger signal is held in a hold circuit (32). An output circuit (33) outputs the held voltage.

Abstract: A non-contacting electrostatic voltage follower employs a vibrating capacitance detector coupled to a measured surface containing both wideband electrostatic A.C. data and D.C. potentials. A detector amplifier having an inverting input is connected to the detector, while its output is connected to the input of a high bandwidth amplifier. A first feedback path is provided from the output of the high bandwidth amplifier to the non-inverting input of the detector amplifier which provides both a signal which is equal to and follows the wideband electrostatic A.C. potentials on the measured surface, and a signal, at the vibrating capacitance modulation frequency, representative of the D.C. potential of the measured surface. A second feedback path is provided including a demodulator and integrator to monitor the first feedback path to provide a D.C.

Abstract: A navigation system for an aircraft fitted with an autopilot, the system comprising at least one ground-based transmitter (2), receiver means (7,8) mounted in the aircraft and including two antenna (5,6) oriented such that their polar diagrams overlap and are inclined with respect to the fore-and-aft axis of the aircraft.

Abstract: A non-contacting voltage metering device for monitoring the electrical potential of a test surface includes a sensing integrator, and a tuning fork mechanism for modulating the capacitive coupling. The integrator input is coupled to the amplifier output and the integrator output is connected to a high-voltage FET output amplifier. The apparatus includes a feedback circuit with a phase sensitive detector which has an input coupled to the integrator output and an output coupled to the integrator input, and a reference terminal coupled to the modulating mechanism for receiving the predetermined frequency.

Abstract: An electrostatic voltmeter with probe for measuring the charge on a surface, the probe comprising a microdeflector unit having a base; a flexible finger supported on the base in cantilever fashion, the finger deflecting in response to a potential difference thereacross; means to bias the base to a predetermined potential; a sensing electrode on the finger having a side positionable in spaced relation to the surface, the capacitive relation established creating a charge representative of the charge on the surface on the sensing electrode causing deflection of the finger; means to impinge a beam of light on the finger; and a detector disposed to detect reflection of the beam by the finger on predetermined deflection of the finger corresponding to a preset charge measured on the surface.

Abstract: A non-contacting electrostatic detector comprising a detector electrode sensitive to an electrostatic quantity, a modulator coupled to the electrode for moving the electrode relative to a surface bearing the electrostatic quantity to which the electrode is exposed to produce capactive modulation of the physical capacitance beween the electrode and the surface, and an amplifier having an inverting input serving as a summing node and a non-inverting input, the electrode being connected to the inverting input and the amplifier being connected as a summing amplifier by an impedance connected between the amplifier output and the inverting input. An a.c. voltage signal having a frequency equal to the frequency of the modulator is applied to the non-inverting input of the amplifier. The amplitude and phase of the a.c.

Abstract: A sensor for an electrostatic voltmeter comprising an elongated vibratory element supported at one end in the manner of a cantilever beam, a sensitive electrode on the vibratory element near the other end and adapted to be disposed toward an electrical field or potential being measured, a driver chip on the vibratory element for vibrating the element in a direction to vary the capacitive coupling between the electrode and the electrical field or potential being measured, and an amplifier on the vibratory element in direct proximity to the sensitive electrode and having an input connected to the electrode and an output adapted for connection to the electrostatic voltmeter. The amplifier is mounted directly on the vibratory element so as to be in synchronous motion with the electrode. Preferably the electrode is mounted on one side of the vibratory element and the amplifier is mounted on the opposite side.

Abstract: A method and apparatus for detecting defective insulators in an insulating column supporting an electrical conductor in a power line. The column is made of a plurality of serially connected insulator members. Voltage present on the conductor supported by the column generates an electric field about it. The presence of faulty insulators within the column causes field redistribution and discontinuities in it. A specially configured electric field probe is provided to measure at predetermined distance and locations, this electric field. A displacement device is provided whereby to displace the probe along an axis substantially parallel along the length of the column to automatically obtain measurements. Means to analyze the measurements are provided and allow to identify the defective insulators whose positions correspond to the locations of the discontinuities in the electric field surrounding the column. The main advantage of this method is that no electrical contact need to be made to the insulators.

Abstract: A method is provided for utilizing a nonintrusive, noncontacting electric field sensing device to detect faults in high voltage transmission line insulators. The electric field surrounding an unfaulted insulator is mapped using a spherical dipole to obtain a characteristic reference curve. The field of a suspect insulator is then mapped to obtain a test curve which is compared with the reference curve to determine the existence of and location of a fault.

Abstract: A surface potential detector of a non-contact type which comprises first and second detecting electrodes arranged in a separated manner from a measured surface so that charge variations are induced on the first and second detecting electrodes on the basis of the potential of the measured surface. The surface potential detector further comprises apparatus for making the amounts of charge variations induced on the first and second detecting electrodes different from each other, first and second detecting devices respectively detecting the amounts of charge variations induced on the first and second detecting electrodes and correction apparatus for performing arithmetic on the ratio between the outputs from the first and second detecting devices to correct the output of the first or second detecting devices on the basis of the ratio.

Abstract: A surface electric potential sensor for detecting an electric potential on a surface of an object without contacting the surface. The sensor comprises a tuning fork having a base and legs formed of a single elastic body, piezoelectric vibrators respectively mounted on the legs, double-layer structure electrodes respectively provided on ends of the legs and each comprising an insulating substrate and a high conductive film, a supporting board, and a shield case which has a window for introducing therethrough lines of electric force radiated from the surface of the object. The tuning fork is mounted at the base on the upper surface of the supporting board. An electric circuit may be also mounted on the upper surface of the supporting board. As the tuning fork is vibrated by the piezoelectric vibrators, the electrodes moves so as to open and close the window of the shield case.

Abstract: For the measurement of the voltage parameters, such as instantaneous value, phase position, absolute value or sign of the high voltage of a high voltage conductor (1), a sensor (15) is conductively connected with a reference electrode and a non-earthed electrode (10) arranged along an equipotential surface in the proximity of the high voltage conductor (1), which electrodes both lie at a defined potential. The reference electrode can be the high voltage conductor (1), a second electrode (50) arranged on an equipotential surface or an auxiliary conductor (57) conductively connected with the high voltage conductor (1). The sensor, which can be a one-sidedly clamped mechanical piezo-oscillator, modulates the brightness of a radiated-in light bundle (32), which is reflected to the measuring device, converted by a receiver (40) into an electrical signal and evaluated.

Abstract: The surface potential electrometer includes a reciprocating chopper, a measuring electrode on which a voltage is induced which is associated with the surface potential of a member to be measured, a shield member for shielding the measuring electrode and the chopper from electric field emanating from the member to be measured, and a driver for driving the chopper, thereby detecting the surface potential of the member in the form of an AC signal. The shield member is provided with an aperture for guiding the electric field emanating from the member to the measuring electrode.

Abstract: This describes a vibrating probe for measuring electrostatic surface potential. A multilayered piezoceramic bender element assembly is provided with a multilayered shield surrounding the bender assembly on all sides except for one opening window. The conductive sense element of the bender assembly is located in the window and is positioned near the surface to be measured. The bender assembly includes a conductive layer sandwiched between a drive piezoceramic layer and a feedback piezoceramic layer. The feedback piezoceramic layer is coated (on the side opposite to the inner conductive layer) with the conductive sense element and with a separate conductive area for connection to a drive oscillator. The multilayered shield is comprised of inner and outer conductive layers sandwiching an insulator. A circuit is provided whereby the sensed signal floats on a high voltage signal applied to the conductive layers of the shield.

Abstract: An electrostatic voltmeter with a microdeflector probe having a base, a flexible finger supported on the base in cantilever fashion, the finger deflecting in response to a potential difference thereacross, separate driven and variable capacitance electrodes on the finger sensing the charge voltage on the surface to be measured, the pickup electrode being electrically coupled to the driven electrode, the resulting charge voltage on the driven electrode changing finger deflection and altering the capacitive relationship between the base and the variable capacitance electrode; a predetermined reference voltage on the base; and a circuit for converting the change in capacitance between the base and the variable capacitance electrode to a signal representing the voltage on the surface. In an alternate embodiment, a second microdeflector is provided which changes capacitance between base and variable capacitance electrode in response to noise, and a control for adjusting the signal in response to the noise signal.

Abstract: Novel apparatus (probe) for sensing and controlling the surface charge on an electro-photographic copier drum in which a hollow, cylindrical, tubular shield member provided with a single elongated aperture therein houses a rotatable charge receiving, insulatingly segmented, rod-like fluted member, the latter extending centrally through the shield member. The elongated slot of the outer shield member extends from edge-to-edge of the drum and in close, spaced proximity thereto. One end of the probe apparatus carries an electromagnetic, Hall effect transducer including a phasing paddle wheel member rotatable with the segmented member for timing and synchronizing the rotation of the probe with the drum rotation. The probe is disposed between two spaced apart drum charging corotrons. The probe senses the surface charge on the drum and compares this charge with a known standard charge level.

Abstract: An electrostatic voltage sensor which includes a surface acoustic wave propagating medium and transmitting and receiving transducers coupled to the medium. The voltage sensor is provided with a separate voltage collecting member different from the electrode for applying a voltage or electric field, and the voltage obtained in the voltage collecting member is varied by a predetermined frequency for being applied to the electrode so as to detect external voltage by the variation component of the oscillating frequency.

Abstract: A panoramic electrostatic field sensor includes a central monitoring electrode for detecting an electrostatic field oriented about a 360.degree. arc peripheral thereto. An apertured housing is concentrically arranged about the monitoring electrode, the housing having circumferentially spaced windows through which the central electrode can "see" any electrostatic field radially disposed with respect to the sensor. A cylindrical shielding cap is rotated in the annular space between the monitoring electrode and the housing, the cap incorporating at least one slot to expose the monitoring electrode periodically to any fields viewed through the housing windows. Electronic means for measuring the voltage in response to the field detected is adapted to activate a static neutralizer for emission of positive and negative ions into the field or to actuate a variety of peripheral indicating or triggering devices which provide signals, alarms or readout functions.

Abstract: A fiber optic sensor system and associated technique is disclosed for measuring an electric field wherein a sensor arm of optical fiber cable is wound about a core member of piezoelectric material. A reference arm of optical fiber cable substantially equal in optical path length to the sensor arm is isolated and connected in parallel to the sensor arm so that coherent light generated by a single mode laser source may be split through the fiber-optic arms and recombined after passage therethrough for phase comparison. When subjected to a local electric field, the core member of piezoelectric material varies in dimensions and thereby causes a change in the strain in the optical fiber cable of the sensor arm. Relative phase changes in the coherent light caused by the resulting optical path length change of the strained sensor arm are detected by a passive homodyne demodulator and determinative of the value of the local electric field.

Abstract: A surface potentiometer comprises a measuring electrode, a chopper for intermittently shielding the electric field between the measuring electrode and an object to be measured, a preamplifier circuit for converting an AC signal induced in the measuring electrode into a low impedance signal, and a printed substrate having the wiring pattern of the preamplifier circuit formed on one surface thereof and the electrode pattern of the measuring electrode formed on the other surface thereof.

Abstract: A voltage and electric field measuring device using light as an operating parameter. An electro-optic crystal, a quarter-wave plate, and a polarization analyzer are arranged in that order in the direction of advancement of applied light. A voltage may be applied to the electro-optic crystal through electrodes arranged thereon. The electro-optic crystal belongs to a cubic system, such as bismuth silicon oxide or bismuth germanium oxide.

Abstract: A sensing element for measuring atmospheric electrical field comprising a fixed detection electrode and a rotating modulator. Between the detection electrode and the rotating modulator there is interposed a fixed apertured screen, conductive of electricity and connected to the sensing element mass. The screen has a peripheral portion protruding relative to the modulator. The sensing element measures both slow field variations and abrupt field variations.

Abstract: An electrostatic recording and printing apparatus having improved control means for clarity of images created on a photosensitive member is provided. Images can be created by line scanning with a laser beam and a startup control means can control the charge potential of the photosensitive surface to a predetermined value prior to exposure by the laser beam and then, subsequently, both the amount of the laser beam and the surface potential can be controlled during operation to ensure optimum reproduction conditions.

Abstract: A high speed temperature controlled, microcircuit electrometer comprising a preamplifier with a very high resistance feedback resistor and temperature sensor on a substrate which is temperature controlled by a thermo-electric module on which the substrate is mounted and which is held within a very small temperature range by temperature control circuitry. The preamplifier, feedback resistor, temperature sensor and thermo-electric module are all enclosed in a hermetically sealed, dry gas environment, maintained at an essentially constant temperature, to reduce the effects of hostile environments, such as temperature changes, vibration, contamination, and humidity. This electrometer operates at high speed and is highly responsive to small current values such as ion currents generated by ionized gas molecules in a mass spectrometer.

Abstract: An electrostatic detector comprising a detector electrode sensitive to electrostatic quantities such as fields, voltages, charges and the like, means for varying the capacitive coupling between the electrode and an electrostatic quantity to which the electrode is exposed, and an operational amplifier having an output and a pair of inputs, one of which is operatively associated with the amplifier summing node. A resistive feedback path is defined between the amplifier output and the summing node, the detector electrode is connected to the one amplifier input so that the detector electrode is operated directly into the amplifier summing node, and the other amplifier input is connected to an electrical reference, such as ground. As a result, the detector electrode is held at virtual ground and the amplifier is operated as a current to voltage converter to cause an output voltage to be generated equal to the product of the input current and the resistance of the feedback path.

Abstract: The surface potential electrometer includes a reciprocating chopper, a measuring electrode on which a voltage is induced which is associated with the surface potential of a member to be measured, a shield member for shielding the measuring electrode and the chopper from electric field emanating from the member to be measured, and a driver for driving the chopper, thereby detecting the surface potential of the member in the form of an AC signal. The shield member is provided with an aperture for guiding the electric field emanating from the member to the measuring electrode.

Abstract: An electrostatic voltmeter for measuring the surface potential of a charged body, includes a detecting electrode locatable adjacent to the charged body, and a vibrating element having a pair of parallel spaced legs between which the detecting electrode is disposed in spaced relation. The vibrating element is vibratable such that the legs move toward and away from the charged body. The vibrating element may extend transversely or parallel to a line connecting the charged body and the detecting electrode.

Abstract: An electrode (12) for sensing a surface potential is connected to a non-inverting input of an operational amplifier (14). The output of the operational amplifier (14) is connected to the inverting input thereof in a voltage follower configuration. The output of the operational amplifier (14) is also connected to one or more shield electrodes (19) which are operatively disposed adjacent to the sensing electrode (12). An offset bias voltage of the operational amplifier (14) is adjusted to cancel an input bias current thereof. An operational amplifier (33) may be mounted on a flat substrate (112), with sensing and shield electrodes (113), (114), (116) formed on the substrate (112) by printing. The shield electrodes (114), (116) surround the sensing electrode (113) and also the operational amplifier (33).

Abstract: The addition of a grounded electrode in a special location with respect to the location of the two sensing electrodes of an existing piston-inverted cylinder apparatus used in the measurement of the electric charge condition of non-conductive particles suspended in a mildly conductive electrolyte such as tap water converts the known apparatus into one whose accuracy, reliability and useful life are greatly increased. The grounded electrode is located nearer the open end of the cylinder than are the two sensing electrodes, and the grounded electrode should have a surface area which is several times that of the two sensing electrodes. All three electrodes must be made of the same metal.

Abstract: A surface potentiometer having a measuring electrode disposed at a predetermined distance from a surface to be measured and in which the electric field between the measuring electrode and the surface to be measured is intermittently shielded by a rotatable chopper to thereby induce an AC signal in the measuring electrode and the AC signal is clamped at a timing corresponding to the position of the chopper relative to the electrode to thereby accurately measure the potential of the surface to be measured.

Abstract: The disclosed device is an electromechanical parametric amplifier. It utilizes, as the required nonlinear mixing element, the square law force of an electric field on the surface of a conductor. In an exemplary device, a wire grid (10) is placed adjacent to a conducting diaphragm (11). The diaphragm (11) is mechanically resonant at the local oscillator (LO) frequency. When a signal from the local oscillator (15) is applied to the grid (10), the diaphragm (11) experiences both the electrostatic force from the grid (10) and electrostatic force from the electric field to be measured. The amplitude of the vibration of the diaphragm (11) at the LO frequency is a measure of the electric field of interest. In an exemplary embodiment the vibration was measured by an electret microphone (12) and a lock-in amplifier (14). The measurement of electric field is important, for example, in industrial environments in which the buildup of static electricity is a problem.

Abstract: Apparatus for detecting and measuring an electrostatic field is disclosed which includes two sensing plates and a rotary blade that is rotated to move over the sensing plates to vary the amount of area of each of the sensing plates exposed to an electrostatic field being measured. A particular width and a particular arrangement of the sensing plates are used for producing a non-symmetrical electric output signal with a repetitive wave-form having a reversal of the peaks in each half-cycle. The dissymmetry of the peaks indicates field polarity information and the amplitude indicates field intensity information. Each sensing plate has a non-linear varying width that decreases from a wide end to a narrower end to develop distinctive characteristics in the wave-form.

Abstract: A large bandwidth non-contacting voltage follower for detecting and following both static or d.c. and dynamic or a.c. data of an electrical field or potential being measured. A probe or sensor includes a pair of voltage sensitive electrodes which are vibrated or oscillated within a housing to vary the capacitive coupling between the electrodes and external field or potential in an inverse manner to induce signals on the electrodes having static and dynamic data from the field or potential. The signals are processed and applied to the input of a voltage follower amplifier, the output of which is coupled to the probe housing as a reference, so that the follower output follows the static and dynamic characteristics of the external field or potential.

Abstract: A cooled, temperature controlled electrometer for the measurement of small currents. The device employs a thermal transfer system to remove heat from the electrometer circuit and its environment and dissipate it to the external environment by means of a heat sink. The operation of the thermal transfer system is governed by a temperature regulation circuit which activates the thermal transfer system when the temperature of the electrometer circuit and its environment exceeds a level previously inputted to the external variable temperature control circuit. The variable temperature control circuit functions as subpart of the temperature control circuit. To provide temperature stability and uniformity, the electrometer circuit is enclosed by an insulated housing.