Abstract: Soil water content gauges based on neutron scattering (NS) have been a valuable tool for soil water investigations for some 40 yr. However, licensing, training, and safet y regulations pertaining to the radioactive source in th ese devices makes their use expensive and prevents use in some situations such as unattended monitoring. A capacitance probe (CP ) gauge has characteristics that would make it seem to be an ideal replacement for NS gauges. We determined the relative precision of two brands of NS gauges (three gauges of each) and a brand of CP gauge (four gauges) in a field calibration exercise. Both brands of NS gauges were calibrated vs. volumetric soil water content with coefficients o f determination (r ) ranging 2 from 0.97 to 0.99 and root mean squared errors (RMSE) <0.012 m m water content. 3 -3 Calibrations for the CP gauges resulted in r ranging from 0.68 to 0.71 and RMSE of 0.036 m 2 3 m water content. Average 95% confidence intervals on predictions were three to five times -3

Abstract: Method and apparatus for making measurements on fluids are disclosed, including the use of a capacitive probe for measuring the flow volume of a material within a flow stream. The capacitance probe has at least two elongate electrodes and, in a specific embodiment of the invention, has three parallel elongate electrodes with the center electrode being an extension of the center conductor of a co-axial cable. A conductance probe is also provided to provide more accurate flow volume data in response to conductivity of the material within the flow stream. A preferred embodiment of the present invention provides for a gas flow stream through a micro-gravity environment that allows for monitoring a flow volume of a fluid sample, such as a urine sample, that is entrained within the gas flow stream.

Abstract: A capacitor type acceleration sensor is disclosed. In this sensor, an acceleration sensing element 1 has two variable capacitors C1 and C2 that are constructed with a couple of fixed electrodes and a movable electrode located between the fixed electrodes. Electrostatic power generation/feedback means 15 applies to the fixed- and movable-electrode pairs such an electrostatic power as to set the movable electrode at a preset reference position in accordance with the output signal of capacitance-difference detector means 10. The electrostatic power is outputted as an output signal of the capacitor type acceleration sensor. In the capacitor type acceleration sensor, another fixed capacitor Cx of which the capacitance value Cx is larger than the maximum capacitance-difference between the variable capacitors C1 and C2 of which the capacitance values vary in accordance with an acceleration, is connected in parallel with the variable capacitor C2. The capacitance (C2+Cx) is larger than the capacitance of the variable capacitor C1, irrespective of the direction of acceleration.

Abstract: A storage capacitor is constituted by a storage capacitor electrode, made of a transparent and conductive film extending substantially all over a substrate, and pixel electrodes overlapping with the storage capacitor electrode via an interlevel insulation layer. The storage capacitor holds charges. The storage capacitor electrode is positioned such that it faces the entire surface of the pixel electrodes. Since the transparent and conductive storage capacitor electrode does not reduce the aperture ratio, the storage capacitor can have a large capacitance. A signal voltage applied to the storage capacitor electrode is determined so as not to activate the thin film transistors which are not selected. A light-shielding layer is present at a position between pixel electrodes on or under the storage capacitor electrode. The light-shielding layer shields the thin film transistors, gate lines and drain lines from incident light, thereby preventing reduction of contrast of displayed pictures. Further, an anti-reflection layer formed by heat treatment is placed on a boundary between the storage capacitor electrode and the light-shielding layer, and is effective in assuring visibility of the picture on the liquid crystal display.

Abstract: A capacitor is fabricated on a base surface by applying a first pattern of electrical conductors (a first capacitor plate) over the base surface with an outer surface of the first pattern of electrical conductors including molybdenum. A first hard portion of a capacitor dielectric layer including amorphous hydrogenated carbon is deposited over the first capacitor plate and the base surface, a soft portion of the capacitor dielectric layer is deposited over the first hard portion, and a second hard portion of the capacitor dielectric layer is deposited over the soft portion. The deposition of the soft portion occurs at a lower bias voltage than the deposition of the first and second hard portions. A second pattern of electrical conductors (a second capacitor plate) is applied over the capacitor dielectric layer which is then patterned. A polymer layer is applied over the first and second capacitor plates, and two vias are formed, a first via extending to the first capacitor plate and a second via extending to the second capacitor plate. An electrode-coupling pattern of electrical conductors is applied over the polymer layer, a first portion extending into the first via and a second portion extending into the second via. Deposition of the capacitor dielectric layer can include using a methylethylketone precursor. Additional capacitor dielectric layers and plates having staggered via landing pads can be layered to increase the capacitance.

Abstract: A receiver having, arranged in this order, an input section, an FM demodulator, to which a frequency-modulated input signal is applied, and an LF section, which FM demodulator includes a pulse shaper and a low-pass filter, the pulse shaper comprising a series arrangement of at least a load and a capacitance, the base-emitter junction of a transistor being arranged across the capacitance, and further including a switching device for charging and discharging the capacitance The pulse shaper generates a low-noise pulse in that charging of a capacitance is started upon an edge of the input signal The capacitance voltage is measured by a single transistor and when the transistor is turned on, the charging current of the capacitance is diverted via the transistor, so that the capacitance voltage is limited The capacitance is discharged upon a second edge, after which the cycle is repeated The output signal of the pulse shaper is a signal which varies with the current through the capacitance

Abstract: An apparatus and method for measuring the variation in the capacitance of a capacitive sensor The apparatus and method include means for constantly applying a constant electrically current to an electrode of the capacitor and means for generating a first series of timing pulses The voltage on the capacitor is compared to a reference voltage and an electrical signal is generated when the voltage on the capacitor reaches a first voltage which exceeds the reference voltage The first series of timing pulses emitted by the generating means from the time that the charging of the capacitor beings until the electrical signal is generated is counted and an output signal is generated corresponding to the number of timing pulses counted An application of the sensor to the measurement of the change in length of a telescoping device such as a shock absorber is also disclosed

Abstract: In a capacitive sensor system, first and second driving signals (S2, S3) opposite in phase are applied to a sensor capacitor (3-1) and a reference capacitor (3-2), respectively, which are both connected to a switched capacitor circuit (4). An output signal of the switched capacitor is sampled by two sample-and-hold circuits (7-1, 7-2) which are operated in different phases of the driving signals. A differential amplifier (8) generates a sensor signal in response to the difference in potential between the outputs of the sample-and-hold circuits.

Abstract: This paper discusses a new method for characterization of matching of capacitors using the so-called floating gate capacitance measurement method. The paper explains this (DC!!) measurement method and then discusses modifications that were implemented to improve the measurement accuracy and repeatability from its original thousands of ppms (0.1 to 0.3%) to values down to 50 ppm. This improved accuracy is necessary for correct characterization of capacitor matching. The method is demonstrated with results from double-polysilicon capacitor matching measurements.

Abstract: A foul-resistant, flow-through capacitor, a system employing the capacitor and a method of separation is disclosed wherein the capacitor has at least one anode and cathode electrode pair. The electrodes are formed of high surface area, electrically conductive material and have an open, preferably straight, fluid flow-through path. Typically, the flow path is formed by a plurality of straight, parallel, spaced apart electrodes with the flow path not greater than one of the X-Y-Z distance components of the capacitor. The flow-through capacitor avoids fouling in use and may be employed with saturated waste or other streams.

Abstract: A ferroelectric based capacitor structure and method for making the same. The capacitor includes a bottom electrode having a layer of Pt in contact with a first layer of an ohmic material. The capacitor dielectric is constructed from a layer of lead zirconium titanate doped with an element having an oxidation state greater than +4. The top electrode of the capacitor is constructed from a second layer of ohmic material in contact with a layer of Pt. The preferred ohmic material is LSCO; although RuO2 may also be utilized. The capacitor is preferably constructed over the drain of an FET such that the bottom electrode of the capacitor is connected to the drain of the FET. The resulting capacitor structure has both low imprint and low fatigue.

Abstract: A circuit for minimizing electrostatic forces in capacitance-based sensor circuits. A sensor includes a movable mass (10) that forms the center electrode of two differential capacitors, a sensing differential capacitor (24) and an actuator differential capacitor (52). The other two electrodes (18, 20, 46, 48) of each differential capacitor are fixed. Oppositely phased high-frequency carrier signals are applied to the fixed electrodes of the sensing capacitor and biasing signals are applied to the fixed electrodes of the actuator capacitor (52). When a force is applied to the sensor, the capacitance of the sensing capacitor changes and the carrier signal, with its amplitude and phase modulated in accordance with the magnitude and direction of the force, appears on the movable mass (10). The signal on the mass (10) is fed back to the fixed electrodes of the sensing capacitor to minimize electrostatic forces between the electrodes of the sensing capacitor. Using a separate negative feedback loop, a signal is fed back to the mass to generate electrostatic forces between the mass and the fixed electrodes of the actuator capacitor to restore the mass (10) to its original position.

Abstract: A four-electrode capacitance-to-period converter designed for capacitance measurements of bilayer lipid membranes is described. The capacitance measurement consists of cyclically charging and discharging the measured capacitance with a constant current, regarding its absolute value. The voltage of the studied capacitor is triangularly shaped. The cycle duration is proportional to the input capacitance. Capacitance measurement with a four-electrode system makes it possible to reduce considerably the errors caused by electrode and electrolyte impedance. It is possible to use high-resistance microelectrodes. The system makes it possible to measure the capacitance at an imposed polarization potential; the voltage oscillates about that value during the measurement. This makes it possible to measure the membrane capacitance as a function of polarization potential. An example is cited of using the capacitance-to-period converter in a computer-controlled measuring system.

Abstract: Apparatus and method for a capacitance-based proximity sensor with interference rejection. A pair of electrode arrays (90) establishes a capacitance on a touch detection pad (12), the capacitance varying with movement of a conductive object near the pad (12). The capacitance variations are measured synchronously with a reference frequency signal to thus provide a measure of the position of the object. Electrical interference is rejected by producing a reference frequency signal which is not coherent whith the interference.

Abstract: A capaciflector sensor system scanned in frequency is used to detect the permittivity of the material of an object being sensed. A capaciflector sensor element, coupled to current-measuring voltage follower circuitry, is driven by a frequency swept oscillator and generates an output which corresponds to capacity as a function of the input frequency. This swept frequency information is fed into apparatus e.g. a digital computer for comparing the shape of the capacitance vs. frequency curve against characteristic capacitor vs. frequency curves for a variety of different materials which are stored, for example, in a digital memory of the computer or a database. Using a technique of pattern matching, a determination is made as to the identification of the material. Also, when desirable, the distance between the sensor and the object can be determined.

Abstract: A continuous liquid level measuring system having a guarded capacitance probe and related drive circuit for providing accurate level measurements, even when measuring the level of ionic and highly viscous fluids The capacitance probe has two parallel electrodes, each constructed of a half-tube section, that are separated from each other by an insulated guard wire The probe is excited by a 1 MHz excitation signal applied across the electrodes The current through the electrodes is a function of the capacitance between the electrodes, which is affected by the relative permitivity of the surrounding liquid The effects of highly viscous ionic liquids that adhere to the probe are reduced by exciting the guard wire with a guard signal that is 180° out of phase from the probe's excitation signal The guard signal changes the electric field existing in the space adjacent the junctions of the two electrodes to reduce any liquid coating effects on the level measurement The capacitance probe is connected to a capacitance measurement circuit through at least one 1:1 ratio pulse transformer for isolation, effectively eliminating the effects of noise currents on the probe's capacitance Preferably, a second pulse transformer is provided to isolate the guard wire

Abstract: An inexpensive voltage control type oscillator suitable for use with a mobile radio communication system within a predetermined frequency band range. The oscillator includes a resonance circuit and an oscillation stage formed on a printed wiring board and operating such that the oscillation frequency of the oscillation stage is varied within a predetermined frequency band range by varying the resonance frequency of a parallel resonance circuit included in the oscillation stage on the basis of a control voltage. The parallel circuit comprises a strip line connected in series with a bias resistor and a chip capacitor connected parallel to the strip line. The strip line has an inductance sufficiently larger than that of the resistor and the chip capacitor has a capacitance value so determined that the capacitor resonates at a predetermined frequency in cooperation with the strip line.

Abstract: A capacitance probe is used by a coordinate measuring machine or machine tool to determine distances from the probe to the workpiece surface at various points over the surface. The probe is calibrated by moving it along a line, which is skewed to the surface. During this movement, a plurality of values of the capacitance and the corresponding values of the actual distance moved along the line are recorded. A datum value for the movement along the skewed line is also determined, which corresponds to a position at which the probe would touch the surface. The probe is calibrated without needing separate independent measurements of the distance from the probe to the surface. The workpiece surface is scanned using the thus-calibrate probe, in which different calibration values are used at different points on the surface, in order to account for the local shape of the surface.

Abstract: A soil water capacitance probe (C-probe) and a neutron probe (N-probe) were calibrated for a fine sand. Data obtained with both probes and by time domain reflectometry (TDR) were compared. Calibrations were linear for the N-probe (R 2 =0.97), and quadratic for the C-probe (R 2 =0.92), based on 30 samples varying from 0.03 to 0.30 volumetric water content. N-probe-measured water contents were better correlated with TDR-measured water contents (R 2 = 0.80). Water-content profiles were measured with both probes in 79 access tubes seven times during the summer of 1992. The C-probe gave greater soil-water estimates than the N-probe, particularly at depths less than 70 cm. Measured water depletion (in 1.5 cm profiles over 2 weeks) averaged 1.2 cm less for the C-probe than the N-probe. For dry or coarse textured soils, changes in water content are difficult to detect with the C-probe. This is partly because of the dialectric response measured by the C-probe: the calibration shows a decreasing slope with lesser water content. The C-probe also measures a smaller soil volume than the N-probe. This provides improved depth resolution, but the C-probe is more sensitive to localized conditions, including disturbance effects resulting from access tube installation

Abstract: A variable capacitor for a high frequency circuit of an electrical appliance includes a chip capacitor mounted on a multilayer circuit board and interdigital capacitors formed at inner layers of the circuit board. A wiring pattern for soldering the chip capacitor is connected with the interdigital capacitors via through holes formed in the circuit board. Capacitance select portions are cut so that the capacitance best-suited to the circuit is obtained. The through holes connected to the interdigital capacitors of the inner layer are selectively disconnected from the wiring pattern for soldering the chip capacitor, thereby obtaining a variable capacitor capable of absorbing fluctuations of the circuit for selecting the best-suited capacitance.

Abstract: A semiconductor integrated circuit fabrication method is provided for forming a capacitor on a semiconductor integrated circuit substrate. A lower capacitor electrode is formed over the semiconductor integrated circuit substrate and a capacitor dielectric is formed over the lower capacitor electrode. The capacitor dielectric is preferably formed of silicon nitride. A reoxidation anneal of the capacitor dielectric is performed at a pressure greater than one atmosphere in order to form an oxide layer over the capacitor dielectric. An upper capacitor electrode is disposed over the oxide layer to form a capacitor. The capacitor is formed as part of a dynamic random access memory cell. A transistor is formed upon the semiconductor integrated circuit substrate and the lower capacitor electrode is formed in electrical contact with a diffusion region of the transistor. The capacitor is formed within an opening in molding material that is deposited over the surface of the semiconductor integrated circuit substrate. The reoxidization anneal of the capacitor dielectric is performed at a temperature in the range of 600° C. to 800° C. at pressures ranging up to twenty-five atmospheres. This forms an oxide layer having a thickness between five angstroms and fifteen angstroms in a period of time short enough to prevent excessive out diffusion of dopants from the diffusion regions of the transistor.

Abstract: A quality and/or flow meter employs a capacitance probe assembly for measuring the dielectric constant of flow stream, particularly a two-phase flow stream including liquid and gas components. The dielectric constant of the flow stream varies depending upon the volume ratios of its liquid and gas components, and capacitance measurements can therefore be employed to calculate the quality of the flow, which is defined as the volume ratio of liquid in the flow to the total volume ratio of gas and liquid in the flow. By using two spaced capacitance sensors, and cross-correlating the time varying capacitance values of each, the velocity of the flow stream can also be determined. A microcontroller-based processing circuit is employed to measure the capacitance of the probe sensors. The circuit employs high speed timer and counter circuits to provide a high resolution measurement of the time interval required to charge each capacitor in the probe assembly. In this manner, a high resolution, noise resistant, digital representation of each of capacitance value is obtained without the need for a high resolution A/D converter, or a high frequency oscillator circuit. One embodiment of the probe assembly employs a capacitor with two ground plates which provide symmetry to insure that accurate measurements are made thereby.

Abstract: A side-by-side capacitor structure in which the side-by-side capacitors are formed using a common dielectric layer, with a capacitor plate electrode shaped as an electrostatic shield for preventing stray capacitance between the side-by-side capacitors. More particularly, a substrate of semiconductive material has first and second contact areas on its top surface. First and second electrodes are located parallel to the top surface of the substrate of semiconductive material, but spaced therefrom by an electrically insulating layer that has first and second contact holes extending therethrough from the first and second contact areas to the first and second electrodes respectively. These contact holes are each filled with a respective conductive plug. The electrically insulating layer has a trench in its surface with first and second sides respectively aligned with an edge of the first electrode and with an edge of the second electrode. A dielectric film extends over the first electrode, the inside of the trench, and the second electrode. A third electrode extends over the dielectric film to form a first capacitor with the first electrode, the first and third electrodes providing the plates of that first capacitor, and to form a second capacitor with the second electrode, the second and third electrodes providing the plates of that second capacitor. A portion of the third electrode extends into the trench as a shield against stray capacitance between the first and second electrodes.

Abstract: A rectification device (4) rectifies an input voltage from an AC power source. First and second switching devices (5, 6) are arranged between a pair of output terminals of the rectification device (4) and alternately turned on/off. A series circuit of a first capacitor (8) and an inductor (7-1) is arranged between the two terminals of one of the first and second switching devices (5, 6) so as to perform a smoothing operation with respect to the frequency of an output from the rectification device (5, 6). A second capacitor (11) serves to form a resonance circuit in cooperation with the inductor (7-1) in accordance with the ON/OFF operations of the first and second switching devices (5, 6). The capacitance of the second capacitor (11) is smaller than that of the first capacitor (8).

Abstract: An integrated circuit capacitor and method for making the same utilizes a ferroelectric dielectric, such as lead-zirconate-titanate ("PZT"), to produce a high value peripheral capacitor for integration on a common substrate with a ferroelectric memory array also utilizing ferroelectric memory cell capacitors as non-volatile storage elements. The peripheral capacitor is linearly operated in a single direction and may be readily integrated to provide capacitance values on the order of 1-10 nF or more utilizing the same processing steps as are utilized to produce the alternately polarizable memory cell capacitors. The high value peripheral capacitor has application, for example, as a filter capacitor associated with the on-board power supply of a passive radio frequency ("RF") identification ("ID") transponder.

Abstract: A capacitive sensor element for pressure sensors comprising a house part based on an electrically insulating material such as glass ceramic material and having on an interior surface a first capacitor plate. An opposing capacitor plate is attached to one side of a diaphragm of an electrically insulating material, which on its other side has an electrically conductive shielding layer that is intended to be connected to ground. The capacitor plates form an electrical capacitor, the capacitance of which is changed when the distance between the plates varies. A second electrically conductive shielding layer is preferably surrounded by the insulating material in the house part between a shielding plate and a thick support plate at a distance from the first capacitor plate. The second shielding layer is also intended to be connected to ground. By arranging the second shielding layer near the capacitor plates they are ensured a uniform electrical surrounding for reduction of the influence of stray capacitances. Further, the thick support plate gives the house part a good mechanical stability.

Abstract: The paper presents a method for the evaluation of variation of capacitance of a dielectric coated two-wire line of parallel cylinders, each of unit radius with a change in thickness of the dielectric along the radial direction. A conformal transformation is used to transform the conductor and dielectric boundaries to appropriate contours extending over a fixed region along the imaginary axis in the transformed plane. Approximating the continuous curve obtained through transformation of dielectric boundaries by a very large number of discrete steps, the expression for the capacitance is derived in the form of a definite integral. Numerical data on capacitance as a function of width of the dielectric in the absence and presence of a conducting ground plane are presented. >

Abstract: A capacitor with a metal-oxide dielectric layer is formed with an upper electrode layer that is electrically connected to an underlying circuit element. The capacitor may be used in forming storage capacitors for DRAM and NVRAM cells. After forming an underlying circuit element, such as a source/drain region of a transistor, a metal-oxide capacitor is formed over the circuit element. An opening is formed through the capacitor and extends to the circuit element. An insulating spacer is formed, and a conductive member is formed that electrically connects the circuit element to the upper electrode layer of the metal-oxide capacitor. Devices including DRAM and NVRAM cells and methods of forming them are disclosed.