Abstract: The device for monitoring internal pipe deposit accumulation is a capacitance-based sensor for monitoring changes in thickness of deposits accumulating on an internal surface of a pipe. The device includes a pipe segment having opposed first and second open ends with at least one valve releasably sealing at least one of the first and second open ends. A first electrode, in the form of an electrically conductive cylindrical shell, is mounted on and surrounds a portion of an external surface of the pipe segment. A second electrode, in the form of an electrically conductive rod, is mounted coaxially within an interior of the pipe segment. An electrical power source is electrically connected across the first and second electrodes to form a cylindrical capacitor and changes in capacitance of the cylindrical capacitor are monitored by a controller.

Abstract: Provided is an ultrasonic probe having an adjustable slew rate, the ultrasonic probe having minimal dimensions and circuit sizes. The ultrasonic probe includes: a transducer; a transmitting circuit; a correcting unit; and a distributing unit. The transmitting circuit includes a transducer driving unit and a current source. The transducer driving unit includes a current mirror of a low voltage transistor and a high voltage transistor. The high voltage transistor is connected to the transducer and the current source supplies an operating current to the low voltage transistor of the transducer driving unit. The correcting unit includes a transmission circuit driving unit replica, a bias unit, and an observing unit. The distributing unit transfers a signal to a current source of the transmitting circuit so that the same current value as the current value extracted by the observing unit flows.

Abstract: An oil quality sensor to determine the quality of deep-frying oil by measuring the capacitance of the deep-frying oil in a deep fryer includes a housing and a hollow space in the housing through which the deep-frying oil is guided. An inlet opening introduces deep-frying oil to the hollow space, and a drain opening guides the deep-frying oil out of the hollow space. A first bent electrode extends along the hollow space, and a second bent electrode extends along the hollow space and is arranged opposite the first electrode, in which case the two electrodes form a capacitor and deep-frying oil is guided through the space formed between these two electrodes to measure its capacitance. A first temperature sensor measures the temperature of the oil used for deep frying that needs to be measured.

Abstract: A measuring instrument for detection of electrical properties in a liquid includes a main body configured to hold a tester, a first pole extending from the main body, and a second pole extending from the main body that is spaced apart from the first pole. The first pole carries a positive probe for attachment to the tester, and the second pole carries a negative probe for attachment to the tester. When the probes are placed in the liquid, electrical properties in the liquid are detected by the tester.

Abstract: Provided is a sensor circuit which can amplify a sensor signal at high speed and with a high amplification factor without increasing the current consumption. The sensor circuit includes a primary amplifier for amplifying in advance a differential output signal which is a current signal of a sensor element, a secondary amplifier for amplifying the amplified differential output signal, a constant voltage generating circuit for maintaining a sensor element driving current to be constant, and a feedback circuit for feeding back a feedback signal to adjust an amplification factor. Most of the currents which pass through the primary amplifier are bias currents of the sensor element.

Abstract: A high-voltage sensing capacitor as an interface apparatus that may be used to attach an indicator unit to a high-voltage AC electrical bus and to provide safety to maintenance personnel. The high-impedance nature of the sensing capacitor effectively isolates the indicator unit from the high-voltage source to which it is connected. The sensing capacitor can be directly mounted between a high-voltage busbar and an indicator unit to provide visual and/or audible alerts to maintenance personnel when high voltage conditions are detected on the busbar. The sensing capacitor is comprised of a portable, unitary capacitive structure that includes a molded insulator body encapsulating two electrodes. The electrodes only partially or incompletely overlap within the insulator body. The electrode spacing and configuration is structured to provide a deliberate amount of coupling between the two electrodes in the presence of an AC electric field.

Abstract: A high-voltage sensing capacitor as an interface apparatus that may be used to attach an indicator unit to a high-voltage AC electrical bus and to provide safety to maintenance personnel. The high-impedance nature of the sensing capacitor effectively isolates the indicator unit from the high-voltage source to which it is connected. Multiple electrical phases can be interfaced using a plurality of such sensing capacitors. The sensing capacitor can be directly mounted to a high-voltage busbar. The indicator unit may provide visual and/or audible alerts to maintenance personnel when high voltage conditions are detected on the busbar by the sensing capacitor. The sensing capacitor is comprised of a portable, unitary capacitive structure that includes a molded insulator body encapsulating two electrodes. The electrodes of the capacitor only partially or incompletely overlap within the insulator body.

Abstract: Electronic circuit for the detection of a capacitive variation on two distinct contact capacitors, (C1, C2), comprising means able of squaring the signals generated by a conventional pulse generator and filtered by two filters (R1, C1-R2, C2), wherein the respective capacitors (C1, C2) are the same said contact capacitors which are connected to a respective terminal to a common ground (G); said means are also able to generate respective signals formed of trains of squared pulses, to compare said two signals and to provide an output signal depending on the result of said signals comparison. Said output signal depends on the phase difference between the pulses of said two trains of squared pulses.

Abstract: A variable capacitance circuit includes a capacitance changing structure constructed by connecting a first construction unit, a second construction unit, a third construction unit, and a fourth construction unit, which each include a first electric element that hinders transmission of a direct current (DC) signal and has a capacitance that changes in accordance with the magnitude of an absolute value of an applied voltage, in the mentioned order in a ring. A voltage measuring apparatus measures the voltage of a measured object and includes a detection electrode capable of being disposed facing the measured object and the variable capacitance circuit described above. A power measuring apparatus includes a current measuring apparatus that measures current flowing in a measured object and the voltage measuring apparatus that measures the voltage of the measured object.

Abstract: A bridge accelerometer system includes four capacitors, wherein two capacitors are formed on each side of a rigid member. The other two capacitors are similarly constructed, except that the rigid member is replaced by a flexured plate. The construction of the plates with respect to the flexured plate is substantially similar to the configuration formed by the rigid member and the other two capacitors, and the fixed capacitors and rigid plate are isolated from the flexured arrangement. The four capacitors are connected to form a bridge generating a bridge voltage signal. The bridge voltage signal is signal processed to generate a digital word. The digital word is linearized and filtered and received in computer for attitude adjustment and velocity control.

Abstract: The present invention discloses a circuit used to couple an input signal to an amplifier circuit. The circuit may contain a diode bridge coupled to an adjustable bias circuit. The current through the bias circuit can be adjusted such that the resistance of the diode bridge can be dynamically configured to change the sensitivity of the diode bridge. The bias circuit may be configured to produce a variable amount of current based on a voltage signal. In another aspect of the present invention, the output from the diode bridge is coupled to an amplifier via a clamp circuit designed to prevent the amplifier from overloading.

Abstract: Invention relates to a capacitive proximity switch with an electrical bridge circuit for detecting of an electrically conducting face (15) approaching or moving away, wherein the electrically conducting face (15) is part of a capacitor (for example C1) of the bridge circuit, wherein at least one capacitor (C1, C2, C3, C4) and possibly at least one resistor (R9, R10) are disposed in the bridge branches of the bridge circuit as further reactances, and wherein the bridge is subjected to an alternating voltage as a bridge feed voltage (ubr). The proximity switch includes a flat multilayer printed circuit board (10) having at least two electrically insulating layers (13, 14), wherein an electrically conducting intermediate layer (11) as a first face of a capacitor is disposed between the two electrically insulating layers (13, 14).

Abstract: An electromagnetic stimulator circuit has a precharge power supply, a capacitor, a set of switches, and a stimulator coil. The switches, which can be implemented using a variety of devices, enable flexible control over the coil current waveform without requiring the physical reconfiguration of circuit elements. The shape of the output current pulse is controlled by the modulation of the switches, and much of the energy applied to the coil is returned from the coil to the capacitor for reuse on the succeeding pulse. Less power is required and less heat energy is generated.

Abstract: A measuring instrument (11) for fill level sensors (4) having a measuring electrode (6) and a compensating electrode (9). The measuring instrument (11) has a bridge circuit whose one bridge branch (21) is formed by two series-connected test resistors (23, 24). The other bridge branch (22) is formed by the measuring resistor (17) on the measuring electrode (6) and the compensating resistor (18) on the compensating electrode (9). Between the two bridge branches (21, 22) a diagonal line (26) with a test switch (27) is provided. The measuring instrument (11) is controlled by the control circuit (13) so that the diagonal line (26) is closed outside of preset test time periods, and interrupted at preset test time periods. The end of the diagonal line (26) located between the two test resistors (23, 24) is connected to the base potential (25) of the measuring circuit (12).

Abstract: There is a large difference in frequency dependent, complex electrical permittivity between genuine and counterfeit documents, including paper currency. Genuine bills have a substantially different complex permittivity which is distinct from the permittivity of counterfeit bills. The invention broadly measures the complex permittivity, &egr;, of the ‘paper’ bills to determine if the bill(s) is genuine or counterfeit. In one aspect, the present invention comprises a device and method for determining the genuineness of a document by measuring the complex permittivity based on the frequency dependent dielectric properties of the document. The complex electric permittivity of a dielectric material is typically read by measuring complex impedance using a capacitor to sense material properties. The document may include an enhanced region comprising an additive that establishes a known permittivity in the enhanced region.

Abstract: An improved process for determining the presence of water in a material is disclosed. A set of electrodes is placed on the surface of a layer of the material being monitored, and an electric field is established therebetween. The phase angle for the electric field at a pre-selected frequency is measured, and compared with a predetermined phase angle for a dry portion of the material. A significant difference between the phase angle for the material being monitored and the predetermined phase angle is indicative of the presence of water in the material. The material being monitored may be an electrical insulating material, e.g., for conductive components in water-cooled electrical generators. Electrical generators monitored in this manner are also within the scope of this disclosure.

Abstract: The focus of this paper is to introduce a novel method for calibrating natural gas flowmeters. This new method can accommodate very large flow rates and it avoids common problems associated with current techniques for meter proving. In this method, the amount of gas accumulated in a vessel of fixed volume is determined by measuring the change in capacitance of the vessel with respect to time. Because the accumulator has a fixed volume the problems inherent with the mechanical motions involved in volumetric provers such as bell provers, piston provers and ball provers are eliminated. Accurate measurements can also be made in larger vessels than would be feasible for gravimetric provers, especially for in situ calibrations. Along with avoiding the fundamental problems associated with current provers, initial studies indicate that accuracies of .+-.0.1% are possible, even for flow rates in large pipelines.

Abstract: A system for the verification of the genuineness of currency. The complex electric permittivity of the currency is read by measuring its complex impedance. A particular capacitor arrangement is used to sense the complex electric permittivity of the paper currency.

Abstract: A circuit for measuring variations in the capacitance of a variable capacr forming part of a sensor includes an oscillator which generates an alternating signal which is supplied to two branches of a detection bridge. The first branch includes the variable capacitor connected in series with a variable capacitance diode. The second branch includes a capacitor connected in series with a variable capacitance diode. A differential stage has each of its in puts connected to the common point of a respective one of the branches. Synchronous demodulation means connected to the oscillator, are connected to the output of the differential stage for delivering a DC unbalance voltage Ve which is injected by a feedback line to the common point of the first branch, thereby continuously balancing the detection bridge.

Abstract: Measurements of the permittivity of samples over a very wide frequency range and a wide temperature range have previously involved such problems as changing parts of the measuring equipment in different regions of the frequency range, substituting one of the components of a bridge used as part of the equipment to obtain bridge balance, and limited permittivity resolution. The present invention employs a capacitance bridge formed by a sample held between electrodes, a series capacitor and a detector comprising a high input impedance amplifier and correlators. The bridge is balanced by applying voltages of known relative amplitude and phase constructed from outputs having relative phases of 0.degree., 90.degree. and 180.degree. of two phase-locked oscillators. The voltages are constructed using phase shifters, attenuators and summer-driver circuits. At low frequencies the applied voltages are obtained from a waveform synthesizer.

Abstract: A device for detecting a coagulation in a mixed phase container, such as a fluidized bed type olefin polymerization reactor, includes at least one coagulation detecting part mounted on an inner surface of the reactor, and a coagulation detecting circuit for outputting an electrical signal in response to a change in capacitance between a main electrode of the coagulation detecting part and the surrounding inner surface of the reactor. When any coagulation is attached on the inner surface of the mixed phase container, the state of production of the coagulation can be obtained from a change in output signal from the coagulation detecting circuit connected to the coagulation detecting part.

Abstract: A device for sorting tablets by capacitive measurement, including a disk rotating between capacitor plates, a tablet fielding device for sequentially metering a series of tablets onto the disk, an arcuate guide assembly for guiding the tablets along a guide path as the disk rotates, and a deflector assembly for deflecting the tablets along one of the possible paths, as a consequence of the capacitance measurement.

Abstract: An improved capacitance bridge type liquid level control system for use in refrigeration applications is disclosed which provides improved apparatus for sealing the probe in its mounting and for insulating same against the condenser reservoir stand pipe in which it is mounted. Improved sealing between the probe and probe body is accomplished through an annular PTFE seal which when compressed pushes inwardly to seal a tubular PTFE insulation against annular ridges in the side of the probe rod proper. The improved probe rod shape also maintains a proper stabilized axial alignment between the probe rod and the probe body.