Abstract: A system and method for protecting electrical contact points on a circuit board from tampering and probing. The system includes a protective cover preventing access to electrical contact points on the circuit board. The protective cover includes: at least one nonconductive material layer, a plurality of electrical contacts coupled to the circuit board, and an irregular resistance pattern joined with the at least one layer of nonconductive material and coupled to the plurality of the electrical contacts. The system further includes a controller that is coupled to the plurality of electrical contacts. The system selects two electrical contacts and determines the resistance between the two electrical contacts. The determined resistance is then compared to a baseline resistance determination for the same set of electrical contacts. A security breach can be identified by a change in resistance from the baseline.

Abstract: The present disclosure generally provides systems and methods of controlling an ion concentration in water, for example, a silver ion concentration. The method of depositing ions in the water includes determining a conductivity level of the water using a reference probe. A power level based on the determined conductivity level is also determined. Power is applied to a deposition probe corresponding to the determined power level using a first electrical circuit, and a concentration of ions are deposited in the water.

Abstract: Internal standard concentration is normalized as an independent parameter through measuring a buffer conductance in a system with characterized reagents and in a defined assay device. The conductivity of a fresh internal standard solution is measured whether in isolation or as part of a system that is subject to a uniform variation such as evaporation or condensation. Collected conductance measurements may be used to normalize assay signals that are dependent upon fluidic channel dimensions, such as fluorescence assay signal measurement.

Abstract: An integrated circuit has an inhomogeneous protective layer or coating over a circuit to be protected, and a sensing circuit (80) arranged to sense a first impedance of a part of the protective coating compared to a reference impedance (CO) located on the integrated circuit. The sensing circuit is able to measure a change in the first impedance, e.g. caused by tampering. The sensing circuit has an amplifier (OTA) having a feedback loop, such that the impedance being sensed is in the feedback loop. The sensing circuit can be incorporated in an oscillator circuit (OTA, Comp) so that the frequency depends on the impedance. Where the impedance is a capacitance, sensing electrodes adjacent to the protective layer or coating, form the capacitance. The electrodes can be arranged as selectable interdigitated comb structures, so that the protective layer or coating extends in between the teeth of the comb structures.

Abstract: A method includes positioning body-electrodes in galvanic contact with a body of a patient and positioning a mapping-tool, having a mapping-electrode, in a plurality of regions in the body. The method further includes tracking the mapping-tool at different positions in each of the regions using a location-measuring system, and for each region, generating a respective set of calibration-currents between the body-electrodes and the mapping-electrode at the different positions in the region. A respective relation is derived for each region between the respective set of the calibration-currents and the different positions, and is used in determining the location of an investigation-tool in response to the different respective relations and investigation-tool-currents.

Abstract: A device for detecting the state of a switch. The device includes a detection circuit which delivers a signal of specified value (Vpullup) when the value of an electrical quantity (RSw) characterizing the state of the switch is less than a threshold called the lower threshold (Rclosed) and/or a signal of different value when the value of the electrical quantity is greater than a threshold different from the lower threshold, called the upper threshold (Ropen). The disclosed embodiments also concern flight control systems, in which the device is implemented, and the aircraft including the systems.

Abstract: A method, program product and apparatus include resistance structures positioned proximate security sensitive microchip circuitry. Alteration in the position, makeup or arrangement of the resistance structures may be detected and initiate an action for defending against a reverse engineering or other exploitation effort. The resistance structures may be automatically and selectively designated for monitoring. Some of the resistance structures may have different resistivities. The sensed resistance may be compared to an expected resistance, ratio or other resistance-related value. The structures may be intermingled with false structures, and may be overlapped or otherwise arranged relative to one another to further complicate unwelcome analysis.

Abstract: The invention measures the vertical component Hz of a magnetic field arising from natural sources (MT) simultaneously at a plurality of points (70) on the sea floor to determine places having a non-zero vertical component Hz indicative of an edge of a resistive body (structure) (40), in order to determine whether or not a sub-bottom geologic structure (20), known from marine seismic measurements, exhibits a resistivity contrast with the surrounding rocks, a positive contrast being interpreted as indicating hydrocarbon charge within the structure.

Abstract: There is provided a sensor threshold circuit that makes available a hysteresis width that is not dependent on the change in a threshold point. Since a bias current IB is generated by a threshold current IT and a threshold adjusting current ICONT, the threshold point is given by a coefficient A and a coefficient K and the hysteresis width |BH| is given by the coefficient K. Accordingly, when the coefficient K is determined, the hysteresis width |BH| is not dependent on the coefficient A and keeps a constant value. In addition, since the coefficient A depends on the resistance ratio, the threshold point is variable by changing a single resistor. Further, when the coefficient K is determined, the hysteresis width |BH| is also determined to be a single value with no variations in its value, no changes according to temperature, and no changes over time.

Abstract: Provided is a semiconductor device including a determination circuit adapted to determine whether a fuse is in a connection or disconnection state. The semiconductor device includes a first and second power supply terminals, a measuring terminal, and at least one trimming detection circuit connected between the measuring terminal and one of the first and second power supply terminals. The trimming detection circuit is constructed by a current supplying element, a series arrangement of a fuse and a switch element, and the determination circuit. The current supplying element and series arrangement are connected in series between the measuring terminal and the one of the first and second power supply terminals. The determination circuit has an input connected to a node between the current supplying element and series arrangement. A voltage at the other of the first and second power supply terminals is applied to the measuring terminal in a normal mode.

Abstract: For measuring a voltage difference between two measurement potentials at the input of a voltage converter that can be controlled via a control input, the measurement potentials are shifted by a voltage potential defined by a first pair of impression currents to obtain a first pair of shifted measurement potentials at the output of the voltage converter. Subsequently, the measurement potentials are shifted by a voltage potential defined by a second pair of impression currents different to the first pair to obtain a second pair of shifted measurement potentials. A controller determines measurement phases, in which the first or second pair of measurement potentials, respectively, is determined. An evaluator determines the voltage difference based on the first voltage difference between the first pair of shifted measurement potentials and based on the second voltage difference between the second pair of shifted measurement potentials and outputs the same at the output.

Abstract: A metal identifying device precisely identifies a metal material in a metal member having a plurality of through-hole portions penetrating through the metal member. The metal identifying device of the present invention includes a measurement unit that obtains a measurement value by measuring an electrical property and/or optical property of a test object, a threshold value determination unit that determines a threshold value with use of a reference value obtained by measuring the property of a metal member having a metal composition to be identified and information indicating a ratio of the through-hole portions to a measurement area in the test object and/or information indicating a configuration of the through-hole portion, and a comparison/identification unit that identifies a metal composition of the test object by comparing the measurement value and the threshold value.

Abstract: Methods and apparatus for open lamp detection in electronic circuits are disclosed. An example apparatus to perform open circuit detection associated with an electrical component included in a device disclosed herein comprises a sampling circuit to attempt to pull a sampling current through the electrical component during initialization of the device, a comparator to compare a result produced by the sampling circuit to a reference value, and a timing circuit to cause the sampling circuit to attempt to pull the sampling current through the electrical component and to cause an output of the comparator to be stored after the comparator has compared the result produced by the sampling circuit to the reference value.

Abstract: Apparatus within power sourcing equipment and a method for determining whether a load within a powered device coupled to the power sourcing equipment via a cable is within an acceptable resistance range. If the load is within the acceptable resistance range, a voltage source is coupled to the load. In one embodiment one recharge interval is employed during which a capacitor is charged based, at least in part, on the voltage drop across the load and one discharge interval is employed during which a capacitor is discharged based, at least in part, on the voltage drop across the load. In a second embodiment, first and second recharge and discharge intervals are employed and prior to initiation of the recharge and discharge intervals, settling time periods are provided.

Abstract: An AC maintain power signature detection circuit in a power sourcing equipment (PSE) for a Power over Ethernet system injects an AC test signal onto a power port of the PSE. The AC test signal is driven onto a first power terminal of the power port through a sense resistor. The voltages across the sense resistor are measured and scaled by first and second resistor dividers having different resistor ratios. The voltage and the scaled voltage at the first power terminal side of the sense resistor have a peak voltage being proportional to the load impedance of the load coupled to the power port. The comparator compares the scaled voltages measured across the sense resistor and generates the output signal indicative of the load impedance at the power port.

Abstract: An AC maintain power signature detection circuit in a power sourcing equipment (PSE) for a Power over Ethernet system injects an AC test signal onto a power port of the PSE. The AC test signal is driven onto a first power terminal of the power port through a sense resistor. The voltages across the sense resistor are measured and scaled by first and second resistor dividers having different resistor ratios. The voltage and the scaled voltage at the first power terminal side of the sense resistor have a peak voltage being proportional to the load impedance of the load coupled to the power port. The comparator compares the scaled voltages measured across the sense resistor and generates the output signal indicative of the load impedance at the power port.

Abstract: One arrangement includes a sense element to convey a current from a source to a load and a compensation element located proximate to the sense element. The compensation element having a resistance that changes proportional to a change in temperature of the sense element. The arrangement further includes an operational amplifier having a first input connected to the sense element, a second input connected to the compensation element and an output that provides an output signal that biases a current through the compensation element in response to a voltage across the sense element. The bias current provides an output signal proportional to the conveyed current and the compensation element provides temperature compensation for the output signal. Other embodiments are also disclosed.

Abstract: Apparatus within power sourcing equipment and a method for determining whether a load within a powered device coupled to the power sourcing equipment via a cable is within an acceptable resistance range. If the load is within the acceptable resistance range, a voltage source is coupled to the load. In one embodiment one recharge interval is employed during which a capacitor is charged based, at least in part, on the voltage drop across the load and one discharge interval is employed during which a capacitor is discharged based, at least in part, on the voltage drop across the load. In a second embodiment, first and second recharge and discharge intervals are employed and prior to initiation of the recharge and discharge intervals, settling time periods are provided.

Abstract: Systems and methods for detecting the mode (a.k.a., state) of a fuse or set of fuses in a device such as an integrated circuit. One embodiment comprises a method for determining three fuse states (uncut, cut, and destroyed) by comparing the fuse voltage with two reference voltages. Each fuse state has a different (indicative) impedance and is associated with a fuse voltage. The fuse voltage is below, between, or above two reference voltages, thereby determining the fuse state. One embodiment includes the fuse in series with a read transistor as well as two reference voltage generators, each comprising a resistor and a transistor (equivalent to the read transistor). Both resistors' impedances are greater than the uncut fuse impedance and one is less than the cut fuse impedance. Two comparators are used to bracket the fuse voltage, indicating that the fuse is uncut, cut, or destroyed.

Abstract: An apparatus for testing characteristic impedance of transmission lines includes a variable resistor, a first comparator, a second comparator, and a counter. One terminal of the variable resistor is coupled to a signal source, another terminal of the variable resistor is coupled to one terminal of a transmission line, and another terminal of the transmission line is idle. The one terminal of the transmission line is coupled to the input terminals of the first and second comparators. The output terminals of the first and second comparators are respectively coupled to input terminals of the counter. An output terminal of the counter is coupled to an adjusting terminal of the variable resistor, the counter adjusts the resistance of the variable resistor according to signals output from the first and second comparators.

Abstract: A sensor device and method for detecting the presence of an analyte in a fluid solution are disclosed. The sensor device system can comprise a substrate and an array of free-standing nanowires attached to the substrate. The array can include individual free-standing nanowires wherein each of the individual free-standing nanowires have a first end and a second end. The first end can, in some embodiments, be attached to the substrate and the second end unattached to the substrate. Such individual free-standing nanowires are configured for electrical communication with other individual free-standing nanowires through the first end. A chip or computer can be electrically coupled to the array of free-standing nanowires for receiving electrical information from the array of free-standing nanowires. In some embodiments a power source can be used to send current through the nanowire array.

Abstract: A guarded sense impedance for use in a measurement instrument includes a sense impedance adapted to have a spatially distributed electrical potential and at least one guard structure adapted to have the spatially distributed electrical potential. The guard structure is arranged to provide a spatially distributed guard potential for the sense impedance.

Abstract: A current measurement circuit to measure the output of a power supply transformer includes a simulation capacitor having a capacitance proportional to a parasitic capacitance of the transformer. The first electrode of the capacitor is coupled to an output winding of the transformer and the second electrode is coupled to a first node, with a second sense resistor coupled between the first node and ground so that current flowing through the simulation capacitor flows through the second sense resistor. Current flowing through a first sense resistor coupled to a second node and to ground has a component representative of the output current of the power supply and a component representative of the parasitic current. A differential amplifier coupled at an inverting input to the first node and at a non-inverting input to the second node generates an output signal that is proportional to the output current of the power supply.

Abstract: A test system includes a circuit assembly having an IC and an external circuit. The IC includes test circuitry used to observe data indicative of target resistances in the external circuit. The test system evaluates the data to determine target resistance values. A first embodiment measures two output voltages responsive to a time varying reference voltage. The two output voltages can be used to determine resistance values in the external circuit. A second embodiment enables logic contention on the IC, controllably fixes a pull-down element on the IC, and controllably sweeps a pull-up element on the IC until the voltage at a node between the pull-down and pull-up elements and coupled to an external circuit exceeds a reference voltage.

Abstract: An exemplary method for examining bonding resistance includes providing a first electronic component having a first and second reference pins. A second electronic component having a third and fourth reference pins is also provided. A first input voltage is applied to the first reference pin. A bias resistor connected between the third reference pin and ground is provided, with the third reference pin serving as an output for providing a first reference voltage. The first reference voltage is measured. Bonding resistance between the first reference pin and the third reference pin is evaluated according to the measured first reference voltage.

Abstract: Signal coincidence detection circuits and methods implemented in such circuits are disclosed. An example signal coincidence detection circuit includes a first differential transistor pair, a second differential transistor pair coupled with the first differential transistor pair and a third differential transistor pair coupled with the first differential transistor pair in parallel with the second differential transistor pair. The circuit also includes a first input signal terminal coupled with the first, second and third differential transistor pairs, wherein, in operation, the first input signal terminal receives a first input signal that is communicated to the first, second and third differential transistor pairs.

Abstract: An infrared radiation image pickup apparatus, the image pickup elements of which are each formed by a bolometer, is disclosed. The resistance value of the bolometer outside a preset range in a given readout circuit associated with a given image pickup element does not affect other readout circuits performing parallel operations with the readout circuit. The readout circuit includes an OP amplifier 5, a non-inverting input terminal of which is connected to an output of a D/A converter 7, a MOS transistor 4, and a switch 6. The MOS transistor 4 has a gate connected to an output terminal of the OP amplifier 5 and has a source connected to an inverting input terminal of the OP amplifier 5 and connected via a horizontal switch 3 to a bolometer 1. The switch 6 is connected between the gate and the source of the MOS transistor 4. The D/A converter 7 receives data for applying a bias voltage to the bolometer 1, and outputs the bias voltage.

Abstract: A transmission device includes a transmission line composed of first and second transmission lines. A first circuit block outputs a non-inverted transmission signal to the first transmission line, and a second output circuit outputs an inverted transmission signal to the second transmission line. The second circuit block comprises an impedance element and a comparison circuit for comparing voltages. The same types of impedance elements as the impedance element are interposed in the first and second transmission lines between the first circuit block and the second circuit block.

Abstract: A printer apparatus includes a photoreceptor, a magnetic roll, an electrode, a current source coupled to the electrode, the current source having a signal generator coupled to an input winding of a transformer that exhibits a parasitic capacitance; and a current measurement circuit. The current measurement circuit includes a simulation capacitor having a capacitance proportional to the parasitic capacitance, the simulation capacitor having a first electrode coupled to a hot terminal of the output winding of the transformer and a second electrode coupled to a first node, a second sense resistor coupled between the first node and ground so current flowing through the simulation capacitor flows through the second sense resistor, a first sense resistor coupled to a second node, and a differential amplifier having an inverting input coupled to the first node and a non-inverting input coupled to the second node.

Abstract: A voltage sensor is described that consists of an arrangement of impedance elements. The sensor is optimized to provide an output ratio that is substantially immune to changes in voltage, temperature variations or aging. Also disclosed is a material with a large and stable dielectric constant. The dielectric constant can be tailored to vary with position or direction in the material.

Abstract: A calibration configuration for setting an adjustable impedance has a voltage divider with a variable resistor and a resistor connected in series, which circuit is supplied with potentials of a supply voltage and has, between the resistors, a partial voltage tap off terminal. A circuit has a further resistor, whose value is in a fixed relationship with a resistance of the first voltage divider resistor, and generates a voltage dependent upon a value derived from the further resistor. The voltage and the partial voltage are fed to a comparator for outputting a comparison result to a downstream control logic unit, which logic unit is coupled to the resistor of the first voltage divider and generates a control signal dependent upon the comparator output signal. The control logic unit control signal is used to set the variable resistor until the voltages fed to the comparator correspond to one another.

Abstract: A circuit for measuring voltage of a battery or group of batteries whose terminals are not directly accessible. The battery or group of batteries can have three leads. First and second leads are connected to the voltage output of the battery and the third lead is connected to the return of the battery. The three leads may terminate in a three prong plug which may plug into a printed circuit board to form a module. The module can be connected into a rack via an edge connector. A battery voltage measurement circuit can be located on another printed circuit board which is also plugged into the rack. This other printed circuit board may be interconnected to the battery module by wire traces within the rack. Thus, there are one or more first connectors between the first lead of the battery or group of batteries and the charger. There are one or more second connectors between the second lead of the battery or group of batteries and an input of the voltage measurement circuit.

Abstract: Disclosed is an intrinsically safe sensor signal processing circuit, permitting lower cost installation and eliminating potential hazard. In the combination of a sensor which measures physical value as process variables in hazardous environment and a safety barrier which is mounted in non-hazardous environment, an intrinsically safe sensor signal processing circuit features the safety barrier for case of mounting, wherein current limiting resistances are connected in series with the sensor and these resistances are also connected to either an output or an inverting input of OP Amps that are considered as a driver or a feeder of the sensor signal. The safety barrier can adopt blocking capacitors instead of said current limiting resistors.

Abstract: An apparatus, system and method maximizes efficiency and accuracy of measuring an oxygen concentration of a measured gas by varying a flow of oxygen ions within a measuring cell (202) in accordance with an output signal of an oxygen sensor cell (206). The pump current (208) through a pump cell (204) is switched between a constant positive current and a constant negative current when upper and lower thresholds of the output signal are reached. The pulse width ratio of the square wave produced by the varying current is compared to a pulse width ratio function derived from a calibration procedure to determine the oxygen concentration of the measured gas.

Abstract: Ramp arrangements and methods in accordance with the present invention can provide the position or velocity of an actuator assembly in a rotating media data storage device while loading or unloading a head connected with the actuator assembly from a disk. One such arrangement comprises a conductive ramp electrically coupled to a conductive suspension lift tab such that a closed circuit is formed when the head is unloaded from the disk. As the suspension lift tab slides along the ramp, the resistance of the circuit changes. By measuring multiple positions at multiple times, a head velocity can be determined. This description is not intended to be a complete description of, or limit the scope of, the invention. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures, and the claims.

Abstract: Ramp arrangements and methods in accordance with the present invention can provide the position or velocity of an actuator assembly in a rotating media data storage device while loading or unloading a head connected with the actuator assembly from a disk. One such arrangement comprises a conductive ramp electrically coupled to a conductive suspension lift tab such that a closed circuit is formed when the head is unloaded from the disk. As the suspension lift tab slides along the ramp, the resistance of the circuit changes. By measuring multiple positions at multiple times, a head velocity can be determined. This description is not intended to be a complete description of, or limit the scope of, the invention. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures, and the claims.

Abstract: An apparatus for evaluating data representing the electrical characteristics of a combustion vessel, the combustion vessel being operable to combust a fuel. The apparatus includes a matrix of nodes 132 arranged on an ohmic material of the combustion vessel, a wire 116A, 116B, 118A, 118B, connected to each respective node 132 and a switch SW1, SW2 connected to each wire and to a current source. A circuit 110A, 110B for reducing leakage currents uses an added series element, optimally a diode D1, and feedback control of the voltage across the diode to a set point of zero volts to effectively reduce the off-state leakage current of each switch SW1, SW2.

Abstract: An interrogation of a switched state of a switch is carried out with a high interrogation current until a closed switch is detected. The following interrogations of the switched state are then carried out with a low interrogation current until a definable time period which runs starting from a detection of the closed switch or until a definable number of interrogations which is counted starting from the detection of the closed switch is exceeded. After the expiry of the time period or the number of interrogations, the interrogation is continued with the high interrogation current until a closed switch state of the switch is detected again.

Abstract: A system and method for measuring the alternating current series resistance of a conductor when transporting large currents on the order of several thousand amperes. The system comprises a current sensor, a current/voltage converter, a voltage divider, a voltage sensor, a null indicator, and a voltage meter. The alternating current series resistance is measured by measuring a real component of a voltage drop over a predetermined length of the conductor, deriving a measurement current from the conductor, converting the measurement current into a measurement voltage, withdrawing an adjustable portion of voltage from the measurement voltage, comparing the adjustable portion of voltage with the voltage drop, adjusting the adjustable portion of voltage to balance the voltage drop, measuring the alternating current, and determining the resistance of the conductor as a function of the value of the adjustable portion of voltage that balances the voltage drop and the measured alternating current.

Abstract: A comparative conductivity detection system includes a sample channel assembly and a reference channel assembly. The sample channel assembly includes a sample-fluid channel, a drive electrode, and a detection electrode. The reference channel assembly includes a reference fluid channel, a drive electrode, and a detection electrode. The channels are formed as trenches in a planar substrate. Each electrode is capacitively coupled to its respective channel through a planar cover over the substrate. The drive electrodes are driven anti-synchronously (180° out of phase), while the signals induced in the detection electrodes are summed. The summed detection signal indicates the comparative conductivity of the sample and reference fluids. The reference fluid can, for example, include non-sample components of the sample fluid so that artifacts due to the non-sample components are cancelled in the comparative conductivity detector output.

Abstract: Disclosed is a current sensing system for measuring the current flowing through a current sensing resistance. The system has a calibration resistance coupled to the current sensing resistance and a pair of input resistances each having a first end coupled to one of the ends of the current sensing resistance and a second end coupled to one of the ends of the calibration resistance. A voltage is created across the calibration resistance and the calibration resistance is set at a predetermined level to compensate for the current sensing resistance deviating from a reference value. The voltage is filtered and amplified to produce an output representative of the measured current.

Abstract: An in-range fault detection system for a full wheatstone bridge element (12) having piezoresistive elements (R1, R2, R3, R4) has bridge outputs (INP, INM) connected to measuring means in the form of a first circuit portion (13) to provide a common mode voltage (VCM). A second circuit portion (14) is used to provide a centering voltage (C*VBRG) equal to the common mode voltage at the time of sensor calibration and a third circuit portion (15) is used to provide a small window voltage (W*VBRG) which is a fraction of bridge voltage. The value (W*VBRG) is subtracted from (C*VBRG) at a first summing circuit (SUM1) and added to (C*VBRG) at a second summing circuit (SUM2) and the results are each compared to the common mode voltage by comparators (Q1, Q2) which are then determined to be within or without a window of valid values by an OR gate (Q3).

Abstract: An arrangement that can be implemented with a simple circuit includes a measuring resistance that can either be connected in addition to a load or connected in place of the load. Furthermore, elements are provided that record the change in resistance resulting from the connection of the measuring resistance and signal when the change in resistance differs from a predefined value.

Abstract: A device for detection of when at test probe of conducting material contacts a liquid surface includes a test probe of conducting material. The test probe is electrically screened by an insulated screen, with a part of the test probe projecting in front of the screen. The test probe is connected to a first alternating voltage source via a first impedance and to one input of a differential amplifier, and the screen is connected to a second alternating voltage source via a second impedance and to another input of the differential amplifier. An output of the differential amplifier is connected to one input of a first multiplicator and to one input of a second multiplicator, and another input of the first multiplicator is connected to a third alternating voltage source, and another input of the second multiplicator is connected to a fourth alternating voltage source.

Abstract: A particle signal processing apparatus which processes a particle signal representative of characteristics of particles includes an amplifier having input and output terminals for amplifying a particle signal including serial pulses to output an output signal including the amplified serial pulses, a filter section for extracting a low frequency component from the output signal of the amplifier so that the extracted component is fed back into the input terminal as a negative feedback signal, and a feedback signal control section for allowing the filter section to fix the negative feedback signal when each of the amplified pulses rises and to hold the fixed negative feedback signal while the amplified pulse is larger than a threshold value.

Abstract: A touch sensor with a sensor surface insulated with respect to ground potential, the sensor surface being connected via a measuring resistor to an a.c. voltage generator, and the voltage across the measuring resistor being used as a difference measuring signal. At least one touch sensor can advantageously be integrated in a sanitary fitting and used to control solenoid valves on water feeds of the fitting. An operating element of the fitting is used as a sensor surface and is connected via a connecting cable to control electronics of the sensor. A method of detecting a touch on an electrically conductive surface, a capacitive touch sensor being used which detects the complex conductance of a human body.

Abstract: A redundant resistor matching detector is provided with constant percentage threshold. The redundant resistor matching detector includes a voltage reference and a first operational amplifier, a second operational amplifier, a first potentiometer and a reference potentiometer. The first operational amplifier has a first input connected to a first potentiometer. The second operational amplifier has a first input connected to the reference potentiometer. The first operational amplifier and the second operational amplifier have a reference input coupled to the voltage reference. An input current mirror is coupled to the first potentiometer providing a first current. A first reference current mirror is coupled to the reference potentiometer providing a reference current. A second reference current mirror has an input coupled to a first output of the first reference current mirror and has a first output coupled to an output of the input current mirror.

Abstract: A method for measuring the resistance of a load, preferably the firing pellet of an airbag, that is connected on the secondary side of a rotary transformer, in which the resistance measurement is largely unaffected by the magnetic coupling between the windings of the transformer. According to this method, the capacitor is partially discharged twice in succession. During the first partial discharge, the capacitor is discharged continuously, and during the second partial discharge, the capacitor is discharged in steps. After the two partial discharges, the residual charge voltages at the capacitor are measured and the difference between the two charge voltages is obtained. This difference is an indication of the resistance of the load connected on the secondary side of the transformer.

Abstract: Current-level monitoring circuitry incorporating a full-time coarse monitor and a part-time fine monitor and capable of generating control signals when the current-level being monitored reaches certain predetermined thresholds. In its preferred embodiment the invention is incorporated into battery-protection circuitry, guarding against both excess charging currents and excess discharging currents. A key concept of the invention is a hierarchical monitoring system incorporating a full-time coarse monitor that activates the fine monitor only when the battery current level enters a certain range and then deactivates it once the level falls out of that range again. Should the current level continue to rise up to the threshold of unsafe battery current, the fine monitor will disconnect the battery. In the preferred embodiment of the invention, the fine monitor operates by comparing, with a predetermined reference voltage, the voltage drop across a fine sensing resistor through which battery current is directed.

Abstract: A contact resistance check circuit and method for verifying that a sufficient electrical connection is established between a source and a sense lead of a Kelvin connection. The circuit includes a microprocessor for driving a transformer that is connected to the source/sense probe (i.e., contact resistance) with an input pulse. The input pulse is altered in relation to the magnitude of the contact resistance to produce a check pulse. A comparator is used to compare the check pulse with a threshold voltage and for generating a fault indication signal. A flip flop then stores the fault indication signal so that the fault indication signal may be monitored by the microprocessor.