Abstract: A system for detecting dry running of a pump includes an inlet device to an intake device of the pump for taking in an electrically conductive liquid, and an electrical resistance structure (20) arranged in the inlet device. The electrical resistance structure has a variable resistance value, dependent on wetting with the electrically conductive liquid.

Abstract: A touch control display panel and a touch control display device are provided. The touch control display panel comprises a substrate having a first extending direction and a second extending direction; and at least one force sensing bridge including a first sensing resistor, a second sensing resistor, a third sensing resistor, and a fourth sensing resistor. The first sensing resistor has a longer extending length in the first extending direction than in the second extending direction. The second sensing resistor has a longer extending length in the second extending direction than in the first extending direction. The third sensing resistor has a longer extending length in the first extending direction than in the second extending direction. The fourth sensing resistor has a longer extending length in the second extending direction than in the first extending direction.

Abstract: A sensor for sensing an external magnetic field along a sensing direction comprises a sensor bridge. The sensor bridge has a first sensor leg that includes a first magnetoresistive sense element and a second sensor leg that includes a second magnetoresistive sense element. The first and second sense elements have respective first and second pinned layers having the same reference magnetization. The first and second sense elements have respective first and second sense layers, each self-biased to have a first sense magnetization. A permanent magnet layer is proximate the second sense element. In the absence of an external magnetic field, the permanent magnet layer magnetically biases the first sense magnetization of the second sense layer produce a second sense magnetization of the second sense layer that differs from the first sense magnetization, and the first sense layer of the first sense element retains the first sense magnetization.

Abstract: A measuring bridge (1) provides a first matching pad (2), a second matching pad (3) and a third matching pad (4), wherein all matching pads (2, 3, 4) comprise at least three resistors (21, 22, 23, 31, 32, 33, 41, 42, 43) which are arranged in a T-structure. A second resistor (32) of the second matching pad (3) is connected to a second resistor (22) of the first matching pad (2), and a third resistor (43) of the third matching pad (4) is connected to a third resistor (23) of the first matching pad (2). A second resistor (42) of the third matching pad (4) can be connected to a device under test (7). A third resistor (33) of the second matching pad (3) can be connected to a calibration standard (5), and a first resistor (31, 41) of the second and the third matching pad (3, 4) are connected in each case to a signal input of an element (11) which suppresses a common-mode component on its two signal inputs.

Abstract: Disclosed is a circuit arrangement for determining a temporal change of an output voltage of a half-bridge circuit during a dead time. In one embodiment, the circuit arrangement includes a first input for applying the output voltage. A capacitive network includes a first and a second circuit node capacitively coupled to the input, and having a terminal for a reference potential. A recharging circuit during the switched-on phase of one of a first and second switching elements, adjusts electrical potentials of the first and second nodes, the electrical potentials each being different from the reference potential. A comparator arrangement, during the dead time, determines a time difference between such times at which the electrical potentials at the first and second node each assume a given potential value, the time difference being a measure for the change with time of the output voltage.

Abstract: A magnetic field sensor assembly for measuring an angular direction of a sensed magnetic field relative to the assembly is disclosed. The sensor assembly includes a sensor of a first type configured to sense an orientation of the sensed magnetic field, a sensor of a second type configured to measure an orientation and a direction of the sensed magnetic field and processing circuitry connected to each of the magnetic field sensors. The processing circuitry being configured to process output signals from the sensor of the first type to determine an uncorrected sensed magnetic field angle and to apply an offset angle to the uncorrected magnetic field angle dependent on a logical combination of signs of output signals from the sensors of the first and second types.

Abstract: A circuit for simulating an electrical load at a terminal of a test circuit having at least one first switch and at least one second switch includes a third switch connected to the first switch of the test circuit via a first external connection point. A fourth switch is connected to the second switch of the test circuit via a second external connection point. The first switch and the second switch are connected via a shared, first internal connection point to the terminal of the test circuit and the third switch and the fourth switch are connected via a shared, second internal connection point such that that the first switch, the second switch, the third switch and the fourth switch form an H-bridge circuit. A voltage source is configured to provide the first and second external connection points with a supply voltage. A controllable voltage source is connected in a transverse bridge branch between the terminal and the second internal connection point. An inductance is active in the transverse bridge branch.

Abstract: A field device, comprising a sensor, and a control/evaluation unit. The control/evaluation unit is implemented on an application-specific integrated circuit—an ASIC—which, in at least a first section and in a second section, is embodied as a dynamically reconfigurable logic chip. In each of the two sections, in each case, a measuring path composed of a plurality of function modules can be configured; wherein the individual sections are spaced apart from one another in such a manner, that a temperature and/or a voltage change in one of the sections has no influence on the other section or the other sections. The control/evaluation unit partially dynamically reconfigures the function modules in the measuring paths as a function of the particular defined safety-critical application, so that the field device fulfills the required safety standard.

Abstract: An apparatus for optimizing a Wheatstone bridge robust in a temperature change, the apparatus including; a voltage difference measuring unit which measures a voltage difference between a current input end and a current output end of the Wheatstone bridge, wherein the Wheatstone bridge comprises a first resistor, a second resistor, a third resistor and a fourth resistor and a tuning resistor; and a resistance tuning controller which detects a resistance ratio of a first distribution resistance and a second distribution resistance of the tuning resistor so that the voltage difference measuring unit measures a maximum voltage difference, and controls tuning of the tuning resistor according to the detected resistance ratio.

Abstract: An apparatus for optimizing a Wheatstone bridge robust in a temperature change, the apparatus including; a voltage difference measuring unit which measures a voltage difference between a current input end and a current output end of the Wheatstone bridge, wherein the Wheatstone bridge comprises a first resistor, a second resistor, a third resistor and a fourth resistor and a tuning resistor; and a resistance tuning controller which detects a resistance ratio of a first distribution resistance and a second distribution resistance of the tuning resistor so that the voltage difference measuring unit measures a maximum voltage difference, and controls tuning of the tuning resistor according to the detected resistance ratio.

Abstract: A pressure sensing apparatus including: at least one deflectable diaphragm having a center, wherein each diaphragm supports: at least one positive piezoresistive gauge and at least one negative piezoresistive gauge coupled in series across a voltage differential in a half-Wheatstone bridge configuration having an output between the positive and negative piezoresistive gauges; and, a compensating piezoresistive gauge coupled in series with the half-Wheatstone bridge configuration across the voltage differential; wherein, the compensating piezoresistive gauge is nearer the center of the diaphragm than the negative piezoresitive gauge, the negative piezoresitive gauge is nearer the center of the diaphragm than the positive piezoresitive gauge, and the compensating piezoresistive gauge linearizes the half-Wheatstone bridge output.

Abstract: An RF bridge circuit without a balun transformer. The RF bridge circuit may include a resistive bridge and a differential detector. The resistive bridge may generate a differential signal that is indicative of a differential imbalance across the resistive bridge. Specifically, the differential signal may be indicative of the ratio of the impedance associated with a DUT and the impedance associated with a reference device. The differential detector may be connected directly to the resistive bridge and may sense the differential signal. The differential detector may convert the differential signal into a differential or single-ended IF signal. The RF bridge circuit may process the differential signal without the use of a balun transformer. The differential detector may include a balanced differential mixer, such as a diode ring, a FET quad, a Gilbert cell, and a harmonic mixer. Alternatively, the differential detector may include a balanced differential sampler, such as a harmonic sampler and a sampling bridge.

Abstract: A directional bridge for measuring propagated signals to and from a source device to a load device where both the source device and load device are in signal communication with the directional bridge is disclosed. The directional bridge may include a first bridge circuit network and a first sensing element in signal communication with the first bridge circuit network. The first sensing element may produce a first measured signal that is proportional to the propagated signals.

Abstract: A method and an apparatus for testing a bridge circuit. The method includes inputting a first test clock to a first conversion unit for triggering the first conversion unit to transfer a test data to a second conversion unit according to rising edges of the first test clock, inputting a second test clock to the second conversion unit for triggering the second conversion unit to output an output data according to falling edges of the second test clock, and controlling the first test clock and the second test clock so that the rising edges of the second test clock are not synchronized to the rising edges of the first test clock. A frequency of the first test clock is an even multiple of a frequency of the second test clock.

Abstract: A transformer circuit is disclosed that minimizes the temperature dependence of an output voltage. A first embodiment of the present invention includes a primary winding coupled to receive a voltage to be sensed and a center-tapped secondary winding coupled at a center point to a first voltage output terminal. The center-tapped secondary winding includes a first secondary winding and a second secondary winding, the secondary windings being coupled through a bridge circuit to a second voltage output terminal. Details of this and other embodiments are disclosed.

Abstract: A differential reflection bridge is provided for a 100 Ohm load, the bridge not being compromised by a translation to a 50 Ohm system. The reflection bridge uses two transmission line baluns. The first traditional balun T1 connects the input signal source to a resistor bridge. The second balun T2 connects between a central node of the resistor bridge and an output OUT as well as a second test port that eliminates a path to ground. With no ground path the bridge is immune to common mode impedance disturbances.

Abstract: An ASIC (14, 14′, 14″) conditions two independent outputs (VINM, VINP) of a full Wheatstone piezoresistive bridge (12) in separate conditioning paths. Each path is provided with a bridge supply voltage (VHB1, VHB2) which can serve as a temperature related input signal to respective offset and gain compensation control circuits. The half bridge outputs are inputted to respective amplifiers (U1, U2) along with a selected percentage of the temperature dependent bridge supply voltage. The outputs of the amplifiers provide a signal proportional to respective half bridge output voltage. In one embodiment, the output of the amplifier (U2) in one conditioning path of one half bridge is connected to the input of an amplifier (U4) in the other conditioning path to provide a signal in the one path proportional to the Wheatstone bridge differential output voltage and in the other path a signal proportional to the Wheatstone half bridge output voltage.

Abstract: A frequency selective improved directivity of a return loss bridge is achieved by generating a counteractive reflected energy vector to cancel a reflected energy vector caused by imperfections, such as parasitic effects and an unbalanced balun, in the return loss bridge. The counteractive reflected energy vector of equal magnitude, but opposite in phase, to the undesired reflected energy vector may be induced into a transmission path between a test port and a coupled port. An open circuit stub in the transmission path between the test port and the coupled port may be used to provide the counteractive reflected energy vector. Alternatively a path across a coupling resistor in a return loss path coupled from the test port to the coupled port may be used to provide the counteractive reflected energy vector, with PIN diodes in the coupled path being used for tunability if desired.

Abstract: A frequency selective improved directivity of a return loss bridge is achieved by generating a counteractive reflected energy vector to cancel a reflected energy vector caused by imperfections, such as parasitic effects and an unbalanced balun, in the return loss bridge. The counteractive reflected energy vector of equal magnitude, but opposite in phase, to the undesired reflected energy vector may be induced into a transmission path between a test port and a coupled port. In one embodiment an open circuit stub in the transmission path between the test port and a coupling resistor coupled to the coupled port may be inserted to generate the counteractive reflected energy vector of the desired magnitude with a transmission line between the open circuit stub and the coupling resistor providing the desired phase.

Abstract: A digital synchro/resolver bridge is provided, which may be operated individually, or optionally, may be interfaced with a computer for inclusion in an automated test system. The digital bridge includes a plurality of relay modules operated by an embedded processor to digitally set taps for a plurality of integral transformer windings. The bridge provides feedback to the computer in the form of status messages and also to the front panel thereof, for local mode (i.e., stand along) use. The resolver bridge utilizes a standard communication interface, such as a conventional RS232 interface. The resolver bridge performs a power-on self-test to insure accurate calibration prior to testing of individual resolvers.

Abstract: A magnetic oxygen analyzer which employes a detector comprising a magnetic pole, heat generator arranged in a non-uniform magnetic field where the intensity of a magnetic field produced by the magnetic pole varies, and a magnetic wind sensor disposed to not be affected by heat produced by the heat generator. A change in electrical resistance of the sensor, caused by change in magnetic wind strength, is detected as the oxygen concentration of a mixed gas. The magnetic wind is caused by the magnetic field produced by the magnetic pole and by heat produced by the heater and is related to the oxygen concentration of the mixed gas exposed to the analyzer. Advantageously, the analyzer of the invention provides improved signal to noise ratio, is immune to ambient temperature, and eliminates the need for precise temperature control.

Abstract: A temperature compensated power detector generally comprises a detector circuit portion, which includes a detector diode, and a temperature compensation circuit portion, which includes a temperature compensation diode, that is operably connected to the detector circuit portion. The detector diode and the temperature compensation diode are connected in DC series with each other and develop substantially identical voltage drops. The detector circuit portion operates to detect a voltage from a power input. However, the detected voltage is subject to alteration due to temperature variations. The temperature compensation circuit portion develops a voltage that is also subject to alteration due to temperature variations. The temperature altered voltage of the temperature compensation circuit portion is used to cancel out the temperature altered voltage of the detector circuit portion allowing the power detector to produce a true voltage output.

Abstract: The output voltage of a Wheatstone bridge type electrical circuit compris four main resistances (J.sub.1 to J.sub.4) having substantially the same ohmic value, R, and substantially the same temperature coefficient of resistance, .alpha., is made independent of temperature differences existing between the branches of the bridge by addition, in each of the branches, of a compensation element (r.sub.1 to r.sub.4) in series with the main resistance, each compensation element being physically located very close to a main resistance situated in one of the adjacent branches of the bridge so as to have the same temperature as that main resistance. The compensation elements have the same ohmic value r and the same temperature coefficient of resistance .beta., with R.alpha.=r.beta., r being less than R and, preferably, r/R.ltoreq.1/2, so as to limit the loss of sensitivity of the Wheatstone bridge to variations in the resistances of the bridge.

Abstract: An SWR bridge with an accompanying set of connector saving adapters for connecting between the test port of the SWR bridge and a test device. The SWR bridge includes a branch opposite the test port which has an impedance set to substantially compensate for the impedance of the connector saving adapters. The connector saving adapters are configured to mate with connectors from two groups of test device connectors in both male and female versions, a first group including 3.5 mm, SMA and 2.92 mm connectors, and a second group including 2.5 mm and 1.85 mm connectors. To compensate for any capacitive mismatch between an adapter configured for a particular group of connectors and a given connector type, either a center conductor pin setback, an inductive counter bore in the outer conductor of the adapter, or a combination of the center pin setback and inductive counter bore may be utilized.

Abstract: In a moisture sensor arrangement for large area layers including a high-frequency electrical generator, a signal travel time measuring apparatus and a reflectometer, all connected to a cable system, at least two independent cables of the cable system are arranged so as to have cross-over points with, and being disposed in spaced relationship but sufficiently close t, one another such that a signal transfer can occur at the cross-over points.

Abstract: A convenient, non-optical method for scanning probe microscopy tip-to-sample distance control based on the impedance change in a shear-force dither piezo. This is accomplished by determining the tip-sample distance by measuring the impedance change in a shear-force piezo-member. A Wheatstone type bridge can be utilized to regulate the tip-sample separation. Alternatively, an electrical bridge, having an output, regulates the tip-sample separation relative to the bridge output by driving the piezo/tip with a sine wave and combining said sine wave with a phase-referenced wave of equal amplitude at a 180.degree. phase shift. The electronic bridge detects impedance changes of about -100 dB across loads with impedance phases between -90.degree. to +90. Power dissipation is determined by measuring changes in electric impedance that a dither piezo presents to an oscillator.

Abstract: A circuit for a combustible gas sensor comprising: a bridge circuit having first and second legs; a first node at a first midpoint in the first leg of the bridge circuit; a second node at a second midpoint in the second leg of the bridge circuit; a first temperature responsive resistive sensor element coupled between the first node and a bottom of the bridge circuit and located in a flow of combustible gas; a second temperature responsive resistive sensor element coupled between the bottom of the bridge and ground and located in the flow of combustible gas; and a voltage control circuit coupled to the first and second nodes and to the top of the bridge circuit for maintaining closed loop control of first and second node voltages at the first and second nodes by varying a bridge voltage at the top of the bridge circuit wherein one of the first and second sensor elements includes a catalyst for stimulating reactions of reactive constituents in the flow of combustible gas.

Abstract: An embodiment of the present invention is a roadway sensor for surface installation in a hole such that a thin ceramic contact sensor may be used to measure and cross-compare fundamental physical antenna parameters of the space immediately above a roadway or bridge surface. Measurements are combined by a microprocessor to discriminate between dry pavement, water (rain), snow and ice above the sensor head. Ambient surface temperature, water depth and ice/slush conditions are determined to estimate any hydroplaning hazard and ice/antifreeze/water mixtures. The sensor comprises an antenna that exhibits a resonant frequency and an input admittance including a real term; a Maxwell bridge coupled to the antenna for detecting the resonant frequency, input admittance and real term; and a frequency sweeping oscillator for driving the antenna at a plurality of frequencies proximate in frequency to the resonant frequency.

Abstract: An RF detector circuit (28), which may be utilized in an output power control loop (10) for an RF transmitter, includes a bridge circuit (50) including a first arm (52) containing a first diode (D2) which rectifies the RF signal and a second arm (54) which contains a second diode (D3) series-coupled to the first diode (D2), and having an RF bypass capacitor (C4). The second diode (D3) serves as a temperature compensator for the first diode (D2). The outputs of the bridge circuit (50) are connected to the inputs of a differential amplifier circuit (32) which provides a signal for use in the power control loop (10). The detector input signal is derived from the sense output of a directional coupler (22). In a second embodiment the compensating diode (D13) has its cathode coupled to the cathode of the rectifying diode (D12), and the full voltage across the rectifying diode (D12) is applied to the differential amplifier circuit (32).

Abstract: A microwave point level instrument is adapted to detect level or change of products in a storage vessel. The instrument includes a microwave transducer periodically developing a pulse of microwave energy. A microwave bridge is driven by the transducer for receiving pulses of microwave energy. The bridge includes a reference arm receiving a portion of each pulse of microwave energy to be altered by a variable impedance tuning circuit. A measurement arm receives another portion of each pulse of microwave energy to be altered by dielectric properties of a product at a process seal installed in a storage vessel, in use. A detector arm develops a microwave signal responsive to imbalance in the bridge between the microwave energy altered by the tuning circuit and the microwave energy altered by the dielectric properties of the product. A sensing circuit is coupled to the bridge detector arm for developing an electrical signal responsive to the microwave signal representing the imbalance.

Abstract: A multiple set point material condition monitoring system is responsive both to the level of material with respect to a sensor and the extent of material coating which has accumulated on the sensor. The system provides an output when a predetermined coating thickness has been exceeded, so that the sensor may be cleaned before the coating can accumulate to the extent where a false level output is generated. The systems include three electrode guarded sensors, a bridge comparing the sensor output with a reference, and a bridge reference which is automatically and repeatedly caused to assume a sequence of values corresponding to material condition set points, one of which causes an output when a predetermined coating thickness has occurred and another of which generates a level output. In one embodiment, separate outputs are provided corresponding to each set point. In another embodiment, a single tri-state output is responsive to both set points.

Abstract: A return-loss detector for a serial digital signal source uses a return-loss bridge circuit to exploit the broadband spectral characteristics of a serial digital signal from the signal source to monitor the termination conditions of a system being driven. A differential pair of serial digital signals from the source are input to the bridge circuit having a reference termination in one leg and the system termination in the other. A broadband detector is used at the output of the bridge circuit to generate an error signal, which is measured by a detector or metering circuit. The measured signal may be displayed as a value in dB or may be input to a comparator to provide an alarm or warning signal to an operator.

Abstract: The invention described a pocket size antenna VSWR indicator having a self-contained low level wideband RF signal source which is applied to an antenna under test through a four arm RF resistive bridge circuit. The bridge circuit has been designed to be very accurate and reliable and provides a novelly positioned reference against which the reflection co-efficient of the transmission system is compared to reliably indicate the VSWR of the system. The bridge circuit provides a flat response over the desired wideband frequency range and over the range of antenna impedances which may be encountered. The RF null or bridge balance is detected in a radio receiver or transceiver tuned to the desired operating frequency, from which an indication of antenna VSWR may be provided. The antenna VSWR may be indicated in a variety of way, such as by means of a numbered or colored dial, a plurality of LEDs or an audio tone shift against an internal reference.

Abstract: In a reflection-coefficient bridge, the voltage drop across a neutral arm of the bridge is supplied to the indicator via a coaxial cable. The center conductor of the coaxial cable is coupled to the one connecting point of the neutral arm of the bridge while the outer conductor thereof is coupled to the other connecting point thereof. The coaxial cable and a parallel-connected line portion constitute a balanced converter or balun. Both the coaxial cable and the line portion are wound onto at least one ferrite core. A d.c. voltage is fed to a test object, which is connected to the bridge by way of a coaxial line, through a compensating winding wound on at least one of said ferrite cores to the end of the line portion which is r.f. coupled to the frame.

Abstract: A floating sampler and directional bridge for use in characterizing the impedance of an integrated device under test from D.C. up to frequencies above 100 GHz. The directional bridge has the structure of a Wheatstone bridge with resistor values selected such that when the input impedance of the device under test matches the output impedance of the source, no voltage develops across two nodes of the bridge. When no impedance match exists, a floating diode/capacitor sampler comprised of two diode/capacitor pairs driven by local oscillator strobe pulses samples the voltage difference between the two nodes of the bridge and outputs an IF signal proportional to the difference. Another pair of diode/capacitor samplers outputs an IF signal proportional to the amplitude of the RF excitation waveform.

Abstract: A test set for use in measuring S-parameters with a network analyzer includes a first directional bridge, a second directional bridge and a single balun with two outputs mounted in an RF housing. A test signal from an RF signal source is transmitted through the test set to a device under test. The first directional bridge separates a signal from the device under test and the test signal, and provides the signal from the device under test to a coupled port. The second directional bridge separates the test signal and the signal from the device under test and provides the test signal to a reference port. The balun includes a coaxial transmission line with its outer conductor grounded at an intermediate location to define first and second balun sections. Ferrite beads are mounted on each of the balun sections. The ends of the first and second balun sections are coupled to the first and second directional bridges, respectively.