Abstract: A method and apparatus are provided for implementing automated electronic package transmission line characteristic impedance verification. A sinusoidal voltage source is coupled to a transmission line test structure for generating a selected frequency. Impedance measuring circuitry is coupled to the transmission line test structure for measuring an input impedance with an open-circuit termination and a short-circuit termination. Characteristic impedance calculation circuitry is coupled to the impedance measuring circuitry receiving the input impedance measured values for the open-circuit termination and the short-circuit termination for calculating characteristic impedance. Logic circuitry is coupled to the characteristic impedance calculation circuitry for comparing the calculated characteristic impedance with threshold values for verifying acceptable electronic package transmission line characteristic impedance.

Abstract: A method of making a resonant frequency tag which resonates at a predetermined frequency. The method involves providing a first conductive pattern having an inductive element and a first land and a second conductive pattern having a second land and a third land which are joined together by a link. The second conductive pattern is overlaid the first conductive pattern such that the second land is positioned over the first land. The third land is in electrical communication with the inductive element of the first conductive pattern. The formed resonant frequency tag is energized to determine if the tag resonates at the predetermined frequency. If the tag resonates properly, the third land is electrically coupled to the inductive element. If it does not, the second conductive pattern is adjusted so that overlapping portions of the first and second lands are changed, altering the capacitance to adjust the resonant tag frequency.

Abstract: A system for the wireless transmission of information and energy between a removable vehicle seat and the vehicle body, in which the vehicle seat is detected by measuring the inductance. In this connection, the period of an oscillating circuit is determined, in which the winding of the primary side, and thus the inductance, is connected. In this context, the frequency of the resonance voltage is determined as a function of time. In this context, the zero crossings of the resonance voltage is measured. Alternatively, the secondary side impedance is additionally measured on the primary side by a forced oscillation, namely by a voltage decay in a resonance circuit in which the winding is connected as inductance. A monitoring of the performance reliability of a firing pellet is thereby implemented.

Abstract: A measured value detecting apparatus includes a measuring unit possessing a winding coil capable of generating an output signal corresponding to a measured value and independent of a direct-current component, a detecting unit possessing a receiving unit for receiving the output signal and determining the measured value based upon the output signal received by the receiving unit, an output transmitting line for transmitting the output signal from the measuring unit to the detecting unit, a potential offsetting means for changing the direct-current component of the output signal on the output transmitting line, and a malfunction detecting means for detecting malfunction of the output transmitting line based upon the direct-current component of the output signal.

Abstract: Methods of and systems for balancing the capacitance of a common series capacitive circuit in a semiconductor-based sensor, such as a humidity sensor, are described. Relative humidity sensors can provide measurements via a series capacitive circuit including a humidity-sensitive dielectric separating a common top plate and first and second bottom plates associated with a first and second capacitor, Cx1 and Cx2. For proper operation, the common top plate should be in capacitive balance. Capacitive balance can be achieved by creating voids within and/or along the common top plate of the sensor. A system for creating voids can include a precision cutting instrument, a measuring device for enabling the measurement of capacitance of at least one of the common series capacitive circuit, Cx1 and Cx2, and power provided from a voltage source.

Abstract: A method and circuit for detecting a change in inductance of a variable inductance element. An oscillating signal has a frequency that varies with inductance of the element. An intermediate voltage is produced at a level that varies according to frequency of the oscillating signal. The intermediate voltage is scaled to produce an output voltage.

Abstract: A test circuit receives a plurality of internal test signals and delivers a group of the plurality of internal test signals onto a bus during an idle state of the bus. The bus is coupled to output pins so that the group of internal test signals can be used in debugging operations. The test circuit may include a multiplexing circuit that receives the plurality of internal test signals as inputs and that delivers a selected group of the internal test signals as outputs. The test circuit may also include a switch that couples the selected group of the internal test signals onto the bus during an idle state.

Abstract: A test system and method determining performance of a merged magnetoresistive read-write head based upon operating the write inductive head of the merged read-write head, measuring the resistance of the read head under certain read current bias conditions and finding which read heads have been damaged by ESD.

Abstract: An apparatus for detecting a low impedance load on an output of a driver circuit electrically connected to a coil of a fluid dispensing gun. The driver circuit provides a plurality of output signals to the coil in response to respective drive signals. Each drive signal has a waveform commanding the dispensing gun to open, and the waveform has a higher magnitude initial peak period followed by a lower magnitude hold period. A feedback circuit provides a difference signal as a function of a difference between each drive signal and a feedback of a corresponding output signal. A diagnostic circuit is connected to the driver circuit and provides an error signal representing a low impedance error as a function of the difference signal crossing a threshold signal magnitude during an occurrence of the peak period of the drive signal.

Abstract: A system is proposed for the wireless transmission of information and energy between a removable vehicle seat and the vehicle body, in which the vehicle seat is detected by measuring the inductance. In a first embodiment, in this connection, the period of an oscillating circuit is determined, in which the winding of the primary side, and thus the inductance, is connected. In this context, the frequency of the resonance voltage is determined as a function of time. In particular, in this context, the zero crossings of the resonance voltage is measured. In a second embodiment the secondary side impedance is additionally measured on the primary side by a forced oscillation, namely by a voltage decay in a resonance circuit in which the winding is connected as inductance. A very simple monitoring of the performance reliability of a firing pellet is thereby implemented.

Abstract: A method for inductively measuring the position of a metal strip is proposed, in which, at least on one side of the strip, a primary coil fed by AC voltage is arranged on one side of a strip edge and a secondary coil is arranged on the other side of the strip edge, which secondary coil measures the voltage which is induced by the primary coil and results from the coupling effect with the primary coil and the metal strip situated in between, in which, as a result of lateral relative movement between the metal strip and the primary and secondary coils, the measurement gradient that can be obtained as a result is determined and compared with a predetermined optimum measurement gradient, whereupon, in the event of a difference, the measurement gradient that has been ascertained is matched electronically to the predetermined optimum measurement gradient and the adapted values then obtained are used for the current strip movement control.

Abstract: The present invention is a button on a device that has the ability to detect when a finger touches or is proximate to the button, especially to cause the initiation of a particular feature/function of the device. The button includes a proximity detector that is operable to sense or detect when a user's finger is proximate or on the button. The proximity detector may take many forms. These forms may be combined to provide greater selectivity. Additionally, sensitivity of the proximity detector may be set via threshold values. Sensitivity of the proximity detector correlates to detection or sensing of a user's finger at various distances from the button. One application is as an autofocus/shutter button on a camera.

Abstract: A circuit capable of detecting natural gas at a wide range of concentrations is disclosed. The gas detection circuit includes a catalytic Wheatstone bridge circuit and an analyzing Wheatstone bridge circuit. A circuit for detecting natural gas, which includes placing a device containing the circuit described above in an area in which the air has a potential of containing natural gas, and monitoring the output signal for indications of the presence of natural gas is also disclosed.

Abstract: A method for generating a control signal after a predeterminable period of time is described. The method includes applying a voltage to an inductor at a beginning of a time measurement; and outputting, via a current threshold value detector, the control signal if a current through the inductor exceeds a predeterminable threshold value. The invention also relates to a timing circuit.

Abstract: This Inductive Displacement Transducer relates to a new and useful set of embodiments for a comparator-type relaxation oscillator circuit where the frequency is controlled by variable inductance. Each oscillation of said circuit discharges a fixed amount of charge such that an increase in frequency increases the total current draw of the circuit.

Abstract: The inductance-change detection apparatus comprises an inductance-change converter that converts inductance-change in coils into voltage to output, a reference-voltage generator that generates and outputs a predetermined reference voltage, a frequency characteristic adder that adds a frequency characteristic similar to that of the converted voltage converted by the inductance-change converter to the reference voltage, a reference-voltage compensator that varies and compensates the frequency spectrum of the reference voltage containing the added frequency characteristic, in parallel in the direction of amplitude, corresponding to a parallel variation of the frequency spectrum of the converted voltage in the direction of amplitude, and an inductance-change detector that compares the converted voltage with the compensated reference voltage to detect inductance changes in the coils.

Abstract: A sensor circuit has coils 3a, 3b whose inductances change in response to a change in a physical quantity. A drive circuit 4A applies an a.c. drive voltage to the coils. A voltage detector circuit 5 senses the voltage across each coil. A current integration circuit 10 integrates the current through each coil starting at the time of a polarity inversion of the drive voltage, and outputs a control signal C1, C2 until the time the integrated value of the coil current becomes zero. A phase detector circuit 6A detects the coil voltage to generate a detection voltage Vd during the time the current integration circuit outputs the control signal. A smoothing circuit 7 processes the detection voltage to output a mean voltage Vm. The sensor circuit eliminates any adverse effects of the internal resistances of the coils by inverting and offsetting the resistive component of the coil voltage during the detection period.

Abstract: A sensor drive circuit which accurately detects the amount of variation in inductance of a coil serving as a variable sensor. A peak detector circuit detects a peak value of a difference signal between a variable-amplitude signal and an intermediate signal to output a peak detection signal as a verification signal to a first input of an error amplifier. The error amplifier has a second input receiving a reference voltage and outputs a control signal to an AGC circuit on the basis of the result of comparison between the peak detection signal and the reference voltage. A peak detector circuit detects a peak value of a difference signal between the variable-amplitude signal and an inverted variable-amplitude signal to output the peak value as an inductance detection signal to the exterior. The AGC circuit performs automatic gain adjustment to output a signal of determined amplitude to a buffer in response to the control signal from the error amplifier.

Abstract: A system for testing a voice coil member of a rotary actuator head stack assembly (HSA) of a disk drive includes a plurality of testing circuits, each of which selectively performs at least one predefined test on the voice coil member. During testing, the head stack assembly is removably mounted on a base plate with the axis of rotation of the head stack assembly normal to the top surface of said base plate. A flat reference coil is disposed in a fixed position parallel to the top surface of the base plate to provide an inductively coupled relationship between the reference coil and the coil under test. The ends of the coil under test are connected to a pair of terminals in the base plate. A polarity test circuit for determining the polarity of the coil under test is connected to the terminals. Other test circuits are selectively connected to the terminals and the tests are conducted in a controlled sequence without the need to move the fragile head stack assembly.

Abstract: An eddy-current apparatus for measuring the conductivity of a conductive material and for reducing the influence of lift-off on conductivity measurements is provided. The apparatus includes a probe for inducing an eddy-current in a conductive material and a digital LCR meter for measuring the impedance of the probe when it is placed near the conductive material. A digital processor uses calibration impedance data obtained from a series of reference materials and an impedance measurement for a test material to produce a conductivity value independent of lift-off between the probe and the test material.

Abstract: In a method and with a circuit for compensating for the temperature of inductive sensors having at least one coil from the inductance of which an output variable is formed as measure for a physical variable to be measured, a variable which is dependent on the resistance of the coil is measured and used for correction upon the forming of the output variable.

Abstract: A compact, wide range inductor capable of being trimmed to a desired frequency value, comprising at least two individually tunable inductive elements of different resolution, disposed upon an insulative support. The inductor is usually placed within a hybrid circuit and trimmed after component population.

Abstract: An electromagnetic contactor assembly with a sensing circuit for determining contactor state based upon the reluctance of the contactor coil. The coil has an electromagnetic coil and a movable contact separated from the coil by a gap when the coil is not energized. Energizing the coil causes the movable contact to close the gap and contact the coil. The determination of the relationship between the reluctance in the coil when the gap is in an open and closed state allows contactor gap status to be measured by measuring the coil inductance. A sensing circuit is added to the drive circuit to measure changes in AC current during the pulse cycle which holds the contacts in this closed position. The sensing circuit measures the AC current and is able to signal contactor status based on that value.

Abstract: The invented circuit includes an I/O driver capable of supplying current to an I/O connector, a current detection circuit that may include a current limit resistor and a differential amplifier, a comparator to compare the level of current to a predetermined level and to produce an output signal based thereon, and a translator to convert the output signal from the comparator into a transistor-transistor logic signal. The device that includes the invented circuit then interprets the logic signal as identifying either a serial I/O system or a LAN I/O system.

Abstract: An open head detection circuit for detecting an open-circuit condition in a magnetic head connected to head contacts. The detector circuit includes a threshold source which generates a threshold voltage that is between a head contact voltage representative of a connected head and a head contact voltage representative of an open head. A comparator, coupled to receive head voltage signals from the head contacts and coupled to the threshold source, compares the head voltage signals to the threshold voltage and generates comparator signals representative of the comparison. Sampling circuitry, coupled to the comparator and coupled to receive write data signals, samples the comparator signals after detection of the write data signals and before the write data signals affect the comparator signals.

Abstract: A load voltage detecting device for use in an apparatus for supplying a current variable with time to a load section. The load voltage detecting device for an apparatus such as a pulsed are welding machine can accurately detect the load voltage from the output voltage of the pulse current supplying section without being affected by the reactor component and the resistance component of the load section and the elements extended to the load section such as the cables and the welding torch.