Abstract: A capacitive proximity sensor (100) comprises a sensor unit (10) and a sense circuit unit (20). The sensor unit (10) includes a sensor electrode (11), a shield electrode (12) and an auxiliary electrode (13). The sensor electrode (11) is connected to a C-V conversion circuit (21) and the shield electrode (12) is connected to a shield drive circuit (24). The auxiliary electrode (13) is connected via a change-over switch (30) to the C-V conversion circuit (21) or the shield drive circuit (24). The capacitance values (C1, C2) switched by the change-over switch (30) and detected at the C-V conversion circuit (21) are compared to arbitrarily set a range of a sense region on the sensor electrode (11).

Abstract: Techniques are provided for estimating defibrillation impedance of an implantable cardioverter/defibrillator (ICD). Briefly, at least two low-voltage resistance values are measured at different voltages using a pair of stimulation electrodes connected to the ICD. High-voltage defibrillation impedance is then estimated by the ICD based on a weighted combination of the measured resistance values. In one example, a set of weight coefficients, calculated during an initial calibration procedure, are applied to the measured resistance values to produce the estimate of the high-voltage defibrillation impedance. The weight coefficients are updated whenever a defibrillation shock is delivered, based on actual defibrillation impedance values measured during the shock.

Abstract: A geometry sensor includes: a detection surface including a plurality of polymer sensor elements and configured to detect an external object, the polymer sensor elements being arranged side-by-side along one or more directions and each generating a voltage according to a deformation; and a detecting section detecting a surface geometry of a region in the external object that is in contact with the detection surface, based on the voltage obtained from each of the polymer sensor elements in the detection surface.

Abstract: In a sensor control circuit, an impedance signal output unit has a HPF, a P/H circuit, a LPF, etc., and detects an element impedance of a sensor element on the basis of an impedance response signal which is alternately changed in response to an alternating current signal supplied to the sensor element. The P/H circuit has an input comparator which inputs an impedance detection voltage Vz after the HPF, a rectifying element connected to the P/H circuit, and a hold capacitor which is charged by the output of the input comparator. The input comparator has a constant current circuit and a transistor. The constant current circuit limits an updating value of a hold voltage value Vph of the hold capacitor every alternating current period. The sensor control device detects the element impedance of the sensor element with high accuracy while preventing influence of noise.

Abstract: An apparatus includes a stable local oscillator, which includes a first control loop. The first control loop includes a first voltage-controlled oscillator configured to generate a first output signal and a first phase-locked loop. The apparatus also includes a frequency up-converter configured to increase a frequency of the first output signal. The apparatus further includes a second control loop configured to receive the up-converted first output signal. The second control loop includes a second voltage-controlled oscillator configured to generate a second output signal and a second phase-locked loop. The second control loop may further include a mixer having a first input coupled to the frequency up-converter, a second input coupled to the second voltage-controlled oscillator, and an output coupled to the second phase-locked loop. A reference frequency source may be configured to generate a signal identifying a reference frequency and to provide that signal to the phase-locked loops.

Abstract: Provided is an electrostatic capacitance type touch panel, wherein lead lines are connected to respective end portions of at least either one of the X electrodes and the Y electrodes respectively, the touch panel further comprises an inspection electrode which is laminated to respective end portions of the at least either one of the X electrodes and the Y electrodes with an insulation film sandwiched therebetween on a side where the lead lines are not connected to the at least either one of the X electrodes and the Y electrodes, and a voltage for inspection is supplied to the inspection electrode during an inspection time and a voltage at the same phase as the drive voltage supplied to the at least either one of the X electrodes and the Y electrodes is supplied to the inspection electrode during a usual operation time.

Abstract: There is provided herein a robot-based electrical system for locating holidays within coated pipe that does not utilize a grounding wire. In a preferred arrangement, the robot will carry a metal rotating brush/capacitive pad combination and changes in the capacitance in the brush/pad circuit will be used to identify imperfections in the interior coating of the pipe and especially those located proximate a girth weld. In another preferred embodiment, a circumferential brush will be used that allows testing of the integrity of the internal coating throughout the length of the pipe as the robot travels the pipeline.

Abstract: There is offered an electrostatic capacity type touch sensor capable of detecting a large number of touch positions with high accuracy. The electrostatic capacity type touch sensor is composed of a touch panel and a signal processing circuit. The touch panel is structured to include first through fourth detection electrodes, first and second common electric potential lines, a common electric potential wiring, a common electric potential terminal and first through fourth output terminals disposed on an insulating substrate. The signal processing circuit is structured to include a clock generator, a selection circuit, a charge amplifier, an A/D converter and an arithmetic unit. The charge amplifier detects a change in capacitance induced by that a finger of an operator touches the first through fourth detection electrodes.

Abstract: Wireless electronic devices include wireless communications circuitry such as transceiver circuitry coupled to an antenna resonating element. The transceiver circuitry and the antenna element may be formed on first and second substrates, respectively. In compact wireless devices, transceiver and antenna matching circuits may be formed on the first substrate. During production testing, a radio-frequency test probe with integrated matching circuitry may be used to mate with a corresponding contact point on the first substrate. The integrated matching circuitry may include resistors, capacitors, and inductors soldered in desired series-parallel configurations within the test probe. When the test probe is mated to the contact point on the first substrate, a test unit connected to the test probe may be used to perform radio-frequency measurements to determine whether the transceiver circuitry satisfies design criteria.

Abstract: A diagnostic Electrochemical Impedance Spectroscopy (EIS) procedure is applied to measure values of impedance-related parameters for one or more sensing electrodes. The parameters may include real impedance, imaginary impedance, impedance magnitude, and/or phase angle. The measured values of the impedance-related parameters are then used in performing sensor diagnostics, calculating a highly-reliable fused sensor glucose value based on signals from a plurality of redundant sensing electrodes, calibrating sensors, detecting interferents within close proximity of one or more sensing electrodes, and testing surface area characteristics of electroplated electrodes. Advantageously, impedance-related parameters can be defined that are substantially glucose-independent over specific ranges of frequencies. An Application Specific Integrated Circuit (ASIC) enables implementation of the EIS-based diagnostics, fusion algorithms, and other processes based on measurement of EIS-based parameters.

Abstract: In one general aspect, an apparatus can include a block defining a temperature control channel therethrough and a defining a sample chamber. The apparatus can also include an electrode disposed inside of the block such that the sample chamber is fluidically isolated from the temperature control channel by the electrode. The electrode can be configured to receive a signal from an impedance analyzer during a dielectric spectroscopy experiment related to a sample included in the sample chamber.

Abstract: A system and method for artifact suppression in soft-field tomography are provided. One method includes obtaining an excitation pattern and applying the excitation pattern to an object, wherein the excitation pattern includes a plurality of frequency components. The method also includes measuring a response at one or more of a plurality of transducers coupled to the object and separating the responses among the plurality of frequency components to suppress one or more artifacts.

Abstract: A method for operating a magneto-inductive flow measuring device having a measuring tube, wherein an at least partially electrically-conductive measured material flows through the measuring tube. For determining flow, there is produced by means of at least one coil arrangement a clocked magnetic field, which at least partially passes through the measured material, wherein the magnetic field is produced by an exciter current, which flows through the coil arrangement. The magnetic field is operated with at least a first clocking, wherein, in a case in which the coil arrangement is free of exciter current, an electrical potential difference is sensed between the measured material and a reference potential by means of at least a first measuring electrode communicating with the measured material.

Abstract: A power integrity analyzer according to an exemplary aspect of the invention includes a parameter inputting unit that inputs parameters to a power-supply current waveform which indicates a variation of a power-supply current value on a time axis of an element, a conversion unit that converts the power-supply current waveform which indicates a variation on the time axis determined by the parameter to a power-supply current spectrum which indicates a variation of the power-supply current value on a frequency axis, an allowable value information storage unit that stores an allowable power-supply voltage fluctuation value of the element, and an impedance calculating unit that calculates a target impedance spectrum on the device indicating the variation of impedance value on the frequency axis based on the power-supply current spectrum and the allowable power-supply voltage fluctuation value.

Abstract: A rotation angle sensor with two or more oscillators which comprises, in each case, striplines fixed on a dielectric support, as sensor elements, such that the oscillators are arrayed in a curve, for angle measurement, or they are arrayed in a straight line, for position measurement. One or more actuating elements, for example eddy-current actuating elements, are passed over the curve or the line to cause relative movement. The striplines are shaped so that the one or more actuating elements (B1, B2) cover more than one oscillator.

Abstract: A demagnetization detection device and a demagnetization detection method thereof are provided. The demagnetization detection device is for use in a power control unit which is electrically connected to a testing permanent magnet motor. The power control unit is electrically connected to a direct current power source. The demagnetization detection device is configured to detect a testing voltage value and a testing current value of the direct current power source, and to compute a testing power value of the direct current power source according to the testing voltage value and the testing current value. The demagnetization detection device determines the difference between the testing power value and a standard power value, and then determines whether the testing permanent magnet motor is in a demagnetization status according to the difference.

Abstract: A multi-function sensor apparatus includes multiple sensing electrodes and a control circuit adapted to receive signals from each of the sensing electrodes and to deem whether the sensing electrodes are in a touched state or an untouched state. The control circuit also is adapted to selectively provide an output based on the sensor's states and the manner in which the sensors came to be in such states.

Abstract: Many of the principles of an oxide semiconductor are still unclear and therefore there is no established method for evaluating an oxide semiconductor. Thus, an object is to provide a novel method for evaluating an oxide semiconductor. Carrier density is evaluated, and hydrogen concentration is also evaluated. Specifically, a MOS capacitor (a diode or a triode) is manufactured, and the C-V characteristics of the MOS capacitor are obtained. Then, the carrier density is estimated from the C-V characteristics obtained.

Abstract: A sensor is provided for testing a porous medium. The sensor includes a plurality of porous elements, a number of electrically conductive interface plates which is one greater than the quantity of elements, and the same number of conductors. Each element operates as a discrete variable capacitor, exhibits a different known liquid release curve, and includes a first axial opening. The elements are stacked one on top of another. Each plate includes a second axial opening. The plates are axially distributed within the sensor such that the first and second axial openings combine to form a longitudinal cavity that extends from the sensor's proximal end to its distal end, and each element is sandwiched between a different pair of plates. A distal end of each conductor is attached to a different one of the plates, and a proximal end is routed through the cavity to the sensor's proximal end.

Abstract: An electrical hand-held device with proximity detection can be placed on a surface and has at least one transmission electrode, at least one reception electrode, and at least one compensation electrode between the transmission and reception electrodes. The transmission and compensation electrodes can be supplied with electric switching signals of predetermined frequency and amplitude. The electric switching signal at the compensation electrode is phase-delayed with respect to the electric signal at the transmission electrode. Alternating electric fields radiated at the transmission and compensation electrodes generate in the reception electrode a current that is representative of an approach of a hand to the hand-held device. The transmission and reception electrodes are arranged such that the impedance between the transmission and the reception electrodes exceeds a predetermined value suitable to keep the current generated in the reception electrode under a predetermined value.

Abstract: A method of detecting the position of the armature (3) of an electromagnetic actuator arranged and able to move between first and second coils (1, 2), in which a voltage jump (UB) is applied to the first and the second coils (1, 2) of the actuator connected in series. The first and the second coils (1, 2) form a voltage divider in accordance with the impedance coil principle. The voltage (U1) of the first coil (1) and the voltage (U2) of the second coil (2) are measured and, from the measurement data for the voltages at the first and the second coils (1, 2), the quotient of the difference (?U) between the two voltage values and the voltage jump (UB), normalized in relation to the size of the voltage jump (UB) is calculated, and a specific armature stroke is correlated one-to-one with each value of the quotient.

Abstract: A system and method for assessing a degree of coupling between an electrode and tissue in a body is provided. Values for first and second components of a complex impedance (e.g., resistance and reactance or impedance magnitude and phase angle) between the electrode and the tissue are obtained. From these values, a coupling index is calculated that is indicative of a degree of coupling between the electrode and the tissue. The coupling index may be displayed to a clinician in a variety of ways to indicate the degree of coupling to the clinician. The system and method find particular application in ablation of tissue by permitting a clinician to create lesions in the tissue more effectively and safely.

Abstract: An insulated fiber sensor apparatus is used in a composite that includes a number of fibers in a matrix. An insulated fiber is connected with the composite and is covered with insulation such that the insulation separates the insulated fiber from the matrix and from the number of fibers in the matrix. Further, a measurement device is connected with the insulated fiber. According to one aspect of the invention, the fibers are carbon fibers.

Abstract: An apparatus for attaching to an electronic device, where the electronic device comprises an electrical connector, a back side, a display arranged on a side opposite to the back side, and lateral sides connecting the back side and the side opposite to the back side is disclosed. The apparatus comprises a first body; an electrical connector; a slot for insertion of a smartcard; a fingerprint reader; and circuitry connected to the electrical connector.

Abstract: A method and apparatus for determining planar impedance tomography of a sample comprising a measurement head unit comprising an impedance sensor; a three-axis actuator assembly, coupled to the measurement head unit, for positioning the impedance sensor relative to a sample; a controller, coupled to the three-axis actuator assembly, for controlling the three-axis actuator assembly to position the impedance sensor at a plurality of locations relative to the sample; and an impedance analyzer, coupled to the impedance sensor, for determining an impedance value at each location in the plurality of locations.

Abstract: The present invention concerns methods for estimating one or more transmission properties of a telecommunications transmission line. Estimates of the line input impedance, Zin at a frequency ƒ, and the line capacitance ? are made. An estimate is then made in dependence of ?, the frequency ƒ and a value ?, where ? satisfies the relationship ? coth (?)=Zin·j??, and ?=2?ƒ. Accuracy may be improved by least squares fitting a curve to a set of intermediate values and then generating an estimate from the coefficients of the curve.

Abstract: The present invention provides a measurement process for determination of the optimum contact pressure among components of a solid oxide fuel cell stack in the packaging process in order that the reduction in performance caused by the packaging process can be reduced. The present invention also provides a measurement apparatus which can carry the measurement process out.

Abstract: A circuit for detecting variation of a resistance value of a resistor with respect to a reference value includes a first resistor; a second resistor; a first current source circuit for supplying current to the first resistor; a second current source circuit for supplying current to the second resistor; a voltage comparator circuit for comparing a voltage across the first resistor and a voltage across the second resistor; and a control circuit for digitally adjusting the supply current of at least one of the first or second current source circuit. A ratio of resistance values of the first and second resistors can be obtained from an adjustment value from the control circuit and result of comparison from the voltage comparator circuit.

Abstract: An apparatus for ascertaining and/or monitoring at least one fill-level of at least one medium in a container according to a travel-time measuring method and/or a capacitive measuring method by means of at least one measuring probe. A capacitive measurement circuit, which produces a low frequency measurement signal on the measuring probe, a time-domain reflectometer measurement circuit, which produces a high frequency, electromagnetic signal sent out as a sent signal and a control/evaluation unit, which controls both measurement circuits are included. Also included is a diplexer, which sends the low-frequency measurement signal and the high-frequency, electromagnetic measurement signal to the measuring probe and effects a signal separation of the high-frequency, electromagnetic measurement signal into the first signal path of the time-domain reflectometer measurement circuit and the low-frequency measurement signal into the second signal path of the capacitive measurement circuit.

Abstract: The application methods in the related art cannot apply a sufficient voltage with a rectangular wave having a short rise time to an electronic circuit. Furthermore, electrostatic discharge test can apply a sufficient voltage but can only apply an oscillating waveform. A TLP generator is used as a rectangular wave generator. The sum of an injection resistance and a matching resistance is set so as to match the characteristic impedance of a transmission line for transmitting a rectangular wave to a test target. A capacitor is connected to a return line of the applied rectangular wave. With this configuration, stable application can be achieved. An error observation function of an electronic circuit gradually increases a peak value of the rectangular wave and determines the immunity based on an application voltage to cause an error for the first time.

Abstract: A set of parameters of an evaluation structure are extracted by applying a radio frequency (RF) signal through a first capacitive contact and a second capacitive contact to the evaluation structure. Measurement data corresponding to an impedance of the evaluation structure is acquired while the RF signal is applied, and the set of parameters are extracted from the measurement data. In an embodiment, multiple pairs of capacitive contacts can be utilized to acquire measurement data. Each pair of capacitive contacts can be separated by a channel having a unique spacing.

Abstract: A signal test apparatus for a serial attached Small Computer System Interface (SAS) device includes an SAS female connector to be connected to the SAS device, an SAS male connector to be connected to a server, first and second pairs of subminiature version A (SMA) connectors, and first and second groups of switches. When the first pair of SMA connectors is connected to an oscillograph to test a pair of output signals from the SAS device, the second group of switches are turned on and the first group of switches are turned off to communicate the SAS device with the server. When the second pair of SMA connector is connected to the oscillograph to test another pair of output signals from the SAS device, the first group of switches are turned on and the second group of switches are turned off to communicate the SAS device with the server.

Abstract: A control valve monitoring system is disclosed. The control valve monitoring system includes at least one sensor connected to one of a valve stem or valve shaft, and the at least one sensor detects a change in mechanical integrity of one of the valve stem or valve shaft. A device for providing data regarding the change in mechanical integrity of one of the valve stem or valve shaft is provided, allowing maintenance of the valve shaft or valve stem to be conducted in an efficient manner.

Abstract: The invention refers to a method for carrying out data collection on electrodes placed on a body for subsequent processing of an electrical impedance tomography image of a corresponding part of said body. In order to improve the resolution of electrical impedance tomography systems without noticeably affecting the signal-to-noise ratio, the method according to the invention comprises the steps of placing the electrodes on a peripheral line around the body, applying a current pattern from a current source to at least one pair of electrodes, and measuring differential potentials between pairs of electrodes, wherein at least one intermediate electrode lies in between each pair of electrodes for measuring the differential potentials and the differential potentials of one current pattern for the subsequent image processing refer to at least three different pairs of electrodes with no electrode used more than twice for each current pattern.

Abstract: An EIT device has a plurality of electrodes (4) that can be arranged on a body in order to reconstruct the impedance distribution of the body with a reconstruction algorithm. The control unit (10) of the EIT device is set up by suitable programming to continuously determine at least one property (e1, . . . , eM) each from the measured signals (U1, . . . , UM) of all measuring channels and to correct measured signals of the measuring channels on the basis of the properties or to adapt the reconstruction algorithm on the basis of the properties.

Abstract: A microwave system for generating microwave energy to tissue according to an energy control algorithm is disclosed. The system includes a microwave generator configured to select an energy control algorithm, programmed in the microwave generator that corresponds to a microwave energy delivery device connected to the generator.

Abstract: A method for testing a characteristic impedance of a signal path routing of a printed circuit board (PCB) controls the test device to test a characteristic impedance of the signal path routing of the PCB to get test data of the signal path routing of the PCB. The method further analyzes the test data of the signal path routing of the PCB get analysis results, generate a test report for storing the test data of each signal path routing of the PCB and the analysis results if all signal path routings of the PCB have been tested.

Abstract: A detecting circuit measures at least one response characteristic of an output channel in an electro-acoustic transducer system. A memory stores a plurality of equalizations, each equalization corresponding to a known electro-acoustic transducer system associated with at least one response characteristic stored in the memory. A processor in communication with the detecting circuit and the memory selects one of the stored response characteristics matching the response characteristic measured by the detecting circuit. In some cases, an appropriate equalization is loaded based on the selected response characteristic.

Abstract: Example methods include calculating a first number of turns of a shield winding included in an energy transfer element of a power supply. A first number of turns of the shield winding is calculated for the power supply to have a low noise current in an input conductor of the power supply. The method then includes increasing the first number of turns to a second number of turns. The power supply is then operated, which generates a first voltage waveform of a voltage between the input conductor and an output conductor of the power supply. An impedance is then inserted between the shield winding and the input conductor. The noise current is reduced by adjusting a value of the impedance until a second voltage waveform of the voltage between the input conductor and the output conductor reverses polarity to be the opposite of a polarity of the first voltage waveform.

Abstract: A method for evaluating a target molecule bound to a probe molecule provided with a marker includes: applying AC voltage between a working electrode provided on a substrate and a counter electrode; and using a signal obtained from the marker on the probe molecule bound to the working electrode when a frequency of the AC voltage is varied, or an average value of the signal, to determine at least one of a Stokes radius or molecular weight of the target molecule, a binding rate between the probe molecule and the target molecule, a binding rate constant therebetween, a dissociation rate therebetween, and a dissociation rate constant therebetween.

Abstract: A touch device includes a first conductive film, a plurality of first electrodes, a first auxiliary electrode, a plurality of second electrodes, a second auxiliary electrode, and a second conductive film. The first conductive film has a first side, a second side, a first area, and a second area. The first electrodes are disposed at the portion of the first side located at a side of the first area. The first auxiliary electrode is disposed at the portion of the first side located at a side of the second area. The second electrodes are disposed at the portion of the second side located at another side of the second area. The second auxiliary electrode is disposed at the portion of the second side located at another side of the first area. The second conductive film is disposed beside the first conductive film.

Abstract: A circuit, system, machine-readable storage medium and method for detecting the presence of a leakage path in a multi-cell voltage source is described. The system includes a detection circuit, the detection circuit having a first, second and third amplifiers, a first input of the first amplifier connected to a first terminal of the voltage source and the first input of the second amplifier connected to a second terminal of the voltage source, a second input of each of the first and second amplifiers connected to a reference capacitor, and an output of each of the first, second and third amplifiers connected to a respective first, second and third outputs of the detection circuit; and a processor having inputs connected to the first and second outputs of the detection circuit.

Abstract: A magnetic sensor that includes a magnetic film deposited on a surface acoustic wave device. The surface acoustic wave device includes an input interdigital transducer and an output interdigital transducer. An RF voltage can be applied at the input interdigital transducer in order to generate acoustic waves, which can travel via the magnetic material to the output interdigital transducer. The application of an external magnetic field alters the conductivity of the magnetic material. Such a change in conductivity attenuates the velocity of the traveling surface acoustic wave and an output frequency due to electro acoustic interaction. The change in the applied magnetic field can be indirectly monitored as a change in output frequency of the SAW device at the output interdigital transducer.

Abstract: Methods and systems are provided for determining a condition of a selected region of epithelial tissue and/or an organ in a body as well as to diagnose disease, susceptibility, premalignancy or cancer and to measure response to therapy, introduction of a drug and to assess the margins of a tumor or resection. The methods utilize through the tissue or organ electrical measurements with alternating current applied using one or more surface or internal electrodes and measuring the electrical response using one or more surface electrodes, preferably in combination with one or more electrodes in direct or indirect contact with epithelium comprising the organ or tissue under test. The methods are also useful in combination with DC measurements on the surface of the organ or tissue under test. Measurement of impedance, admittance, electropotential and dielectric properties is particularly useful, particularly as a function of frequency and position on and in the tissue or organ.

Abstract: In one aspect, the present invention provides an imager, preferably portable, that includes a source of electromagnetic radiation capable of generating radiation with one or more frequencies in a range of about 1 GHz to about 2000 GHz. An optical system that is optically coupled to the source focuses radiation received therefrom onto an object plane, and directs at least a portion of the focused radiation propagating back from the object plane onto an image plane. The imager further includes a scan mechanism coupled to the optical system for controlling thereof so as to move the focused radiation over the object plane. A detector optically coupled to the lens at the image plane detects at least a portion of the radiation propagating back from a plurality of scanned locations in the object plane, thereby generating a detection signal. A processor that is in communication with the detector generates an image of at least a portion of the object plane based on the detection signal.

Abstract: A proximity detection system for an appliance is disclosed. The system includes an electrically conductive sensor for a capacitive proximity detection system, the sensor forming a part of an accessory device for the appliance; and an electrically conductive member disposed substantially opposite a location of the sensor and electrically connected to a ground potential to form a ground shield for the sensor.

Abstract: An apparatus for electrical impedance imaging has electrodes arranged on an electrode carrier in an arrangement including a unit of repetition. The unit of repetition repeats over the electrode carrier and has an angle of rotational symmetry less than 90°. Specifically, the unit of repetition is an equilateral triangle or a hexagon.

Abstract: A bridge module provides connection between first and second conductors of a line under test and a test instrument adapted for use with the bridge module. The bridge module provides monitoring and measurement of DSL communication signals between the telephone company DSL terminal (DSLAM) and the subscriber home DSL equipment across a wide range of frequencies. The bridge module can be used at any point in the communications link and can be used while the link is active. The bridge module provides a clickless connection to the active DSL communications link to avoid interruption in DSL service.

Abstract: A catalyst supported on a substrate includes a heater embedded in a sub-region of the substrate to heat a local region of the catalyst. The amount of ammonia stored on the catalyst may be determined and controlled through conductivity measurements in the locally heated portion of the system described.

Abstract: A circuit, system, machine-readable storage medium and method for detecting the presence of a leakage path in a multi-cell voltage source is described. The system includes a detection circuit, the detection circuit having a first, second and third amplifiers, a first input of the first amplifier connected to a first terminal of the voltage source and the first input of the second amplifier connected to a second terminal of the voltage source, a second input of each of the first and second amplifiers connected to a reference capacitor, and an output of each of the first, second and third amplifiers connected to a respective first, second and third outputs of the detection circuit; and a processor having inputs connected to the first and second outputs of the detection circuit.