Showing papers on "Bridge circuit published in 1983"

Controller for a brushless DC motor

Abstract: A controller for regulating the current applied to the windings of a brushless DC motor by pulse width modulating transistors arranged in a six-switch bridge. Current feedback signals are obtained from sense resistors provided in the lower legs of the bridge circuit and are employed to generate a loop error signal. A bilateral arrangement of hysteresis comparator circuits monitors the current feedback signals and provides signals that disable the transistor switches when the current is sensed to be in excess of a safe level of operation for the transistors. The shutdown circuit continues its disablement of the transistors until the current is sensed to fall back within the designed range of control. To ensure smooth transition between regenerating and motoring modes, a circuit monitors both positive and negative excursions of the integrated error signal. When the error signal is sensed to exceed the operating range of the pulse width modulation circuitry, the sense of the motor excitation is reversed in order to produce the desired motor torque. An absolute value circuit enables the use of both positive and negative values of the error signal to control the production of pulses by the pulse width modulation circuit.

High-voltage DC-transmission power station in a block circuit

Abstract: In this high-voltage DC-transmission power station in a block circuit, the generator (2) is connected directly, that is to say without a converter transformer, to a high-voltage DC-transmission back-to-back link (3). The back-to-back link is connected via a network transformer (4) and a three-phase line (5) to a distribution network (6). The generator (2) has two separate three-phase stator windings (9,10) for in each case half the rated power, which are arranged spatially offset such that two three-phase systems are produced which are phase-shifted by 30 DEG electrical with respect to one another and can be connected to the input terminals of in each case one three-phase bridge circuit (11,12) which is used as a rectifier (3a) of the back-to-back link. In order to form a 12-pulse block circuit, the two bridges (11,12) can be connected in parallel or in series.

Pressure sensor employing semiconductor strain gauge

Abstract: Four semiconductor strain gauges constitute a bridge circuit. This bridge circuit and a sensitivity temperature compensation circuit are connected in series, and a constant voltage is applied to the series circuit. The sensitivity temperature compensation circuit varies a voltage across the bridge circuit, depending upon temperatures. The constant voltage is divided to produce a predetermined voltage. The predetermined voltage is selected to be equal to the voltage of one output side node of the bridge circuit at the time when the semiconductor strain gauges are unstrained and at a predetermined temperature. The point of this voltage and the output side node are connected through a resistor so as to perform zero-point temperature compensation.

Pressure transducer with temperature compensation circuit

Abstract: A pressure transducer is disclosed comprising a pressure sensor portion having gage resistors in bridge formed on a thin diaphragm of a semiconductor substrate, and a power supply connected to the pressure sensor portion for driving the pressure sensor. The power supply includes a first current source for supplying a temperature-dependent current equivalent to the sum of a current almost proportional to the absolute temperature and a current independent of temperature, and a second current source for sinking the current almost proportional to the temperature characteristic of the gage resistors from the current of the first current source. A temperature compensation circuit is additionally provided to drive the bridge circuit by the difference between the temperature-dependent current and the current proportional to the temperature characteristic in a constant-current driving mode, and by a voltage proportional to the current difference when the output of the bridge circuit is connected to an amplifier whose gain is dependent on temperature.

Method and apparatus for shutting off a power screwdriver

Abstract: A power screwdriver that is equipped with a spring coupling between the motor drive and the tool spindle, a signal that indicates that a certain value of torque has been overstepped, at which the screwdriver must be sopped, first causes reversal of the motor, but before the motor appreciably turns in the reverse direction, powers shut-off, allowing the motor to coast. After another brief interval, power is reapplied to the motor in the original direction, again briefly. In this way it is possible for the final shut-off to occur when the motor is stopped and the spring is unstressed, avoiding oscillations of the motor-spring system. A triac bridge circuit makes possible quick reversals and brief applications of power. In such a bridge circuit, precautions must be taken to be sure one pair of triacs is extinguished before the other pair is ignited.

Load cell with adjustable bridge circuit

Abstract: A load cell, of the type that converts the magnitude of an applied load into an electrical signal, has a circuit board designed to facilitate wiring The load cell includes a load cell body, strain gauges attached to the load cell body, and the circuit board which also is attached to the load cell body The circuit board is composed of a flexible board, a wiring pattern formed on the flexible board, and soldering portions provided on the wiring pattern on either side of a bending portion at which the flexible board is bent for attachment to the load cell body Symbol marks for identifying terminals are provided adjacent prescribed terminals of the wiring pattern formed on the circuit board

Method and apparatus for tuning percussion instruments

Abstract: A tuning device for tympani that displays the pitch of each instrument's tympanum. The pitch is determined by measuring the strain in an adjustable tensioning mechanism employed in all tympani to keep proper tension on the tympanum. The pitch or tone of the tympani is determined by the vibration frequency of the tympanum when the tympani is played and the frequency is determined by the tension in the tympanum. A transducer measures the strain in the tensioning mechanism to give an accurate indication of what the tympanum tension, and therefore the pitch, of the tympani would be when played. The transducer includes a resistance-type strain gage mounted on the tympanum tensioning mechanism. The length of the conductor in the strain gage and therefore its resistance, changes with stress changes in the tensioning mechanism used to tune the tympani. A switch means selects a desired one of the strain gages mounted on each of the one or more tympani for inclusion as one section of a four-section resistance bridge circuit configuration. A signal conditioning module provides excitation to the bridge circuit and also conditions the output of the bridge circuit. The output of the bridge circuit varies as the resistance of the strain gage varies. The conditioned output of the bridge circuit is displayed on a voltmeter whose scale has been calibrated to indicate the pitch of the tympani being monitored.

Device for the pick-up of measured values

Abstract: A device for the pick-up of measured values having a frame forming a first measurement reference and an element movable relatively to the frame and forming a second measurement reference. The device includes a carrier connected to the element forming the second measurement reference and a mechanical/electrical conversion system connected between the frame and the carrier. The conversion system produces a magnetic field directed at right angles to the direction of movement of the carrier and has at least one air gap within which the carrier is arranged to move at right angles to the magnetic field. Two pairs of field plates are arranged in the air gap and when the carrier is moved the extent of penetration of the pairs of the field plates by the magnetic field is changed. The device also includes a bridge circuit by which the field plates are connected. The bridge circuit includes in one diagonal thereof a device for the display of measured values and is connected across the other diagonal thereof to a d.c. voltage.

Self resonant power supply for electro-acoustical transducer

Abstract: A motional bridge circuit for generating feedback signals proportional to the vibration of an ultrasonic transducer is modified by means of an active filter in the feedback circuit which is coupled to a starting circuit that raises the Q of the active filter when a signal is not present in the feedback loop to change the active filter from a mode suppressant to a self-oscillating state.

Electronic tripping circuit for a delayed fault current protection circuit

Abstract: The fault current protection circuit comprises a current transformer, which detects the fault current and whose secondary winding (1) supplies a rectifier bridge circuit (3) downstream of which there are connected an energy storage device (7) and a time-delay circuit (8, 12, 13), by means of which a switching device (14) is driven which is connected in series with the coil winding (17) of a tripping device. The bridge circuit (3) contains semiconductors (5) which protect the circuit against overvoltages. The time-delay capacitor (13) is charged via a constant-current regulating element (8). The switching device (14) is connected to a reference voltage (23) which is formed by a resistor (19) and a zener diode (20).

Constant temperature anemometer having an enhanced frequency response

Abstract: A constant temperature anemometer having an enhanced frequency response. A sensor element is included within one leg of a bridge circuit with a feedback circuit being operatively connected to the bridge circuit. The bridge circuit frequency response is shaped by impedance elements connected in parallel with another leg of the bridge circuit. In a preferred embodiment, the impedance elements include serially connected resistance and capacitance elements.

Transistorized bridge rectifier circuit with overcurrent protection for use in telephones

Abstract: A transistorized bridge rectifier circuit with overcurrent protection which can be integrated monolithically is used for joining to a two-wire telephone line to the electronic circuits of a telephone subscriber set connected thereto. The circuit includes a transistorized bridge having a circuit arranged in the manner of a Graetz bridge. Rather than using separate elements for overcurrent protection, the circuit uses the bridge circuit elements themselves as protection elements. Diodes or diode connected transistors are respectively connected between the base and collector of transistors in two arms of the Graetz bridge and the resultant circuit thus provides overcurrent protection without the need of additional protection elements.

Superconducting fault current limiter and inductor design

Abstract: A superconducting fault current limiter (SFCL) that uses a biased superconducting inductor in a diode or thyristor bridge circuit was analyzed for transmission systems in 69, 138, and 230 rms kV utility transmission systems. The limiter was evaluated for costs with all components--superconducting coil, diode and/or SCR power electronics, high voltage insulation, high voltage bushings and vapor cooled leads, dewar, and refrigerator--included. A design was undertaken for the superconducting cable and coils for both diode and SCR 69 kV limiter circuits.

Measuring device for the liquid level in a container

Abstract: Use can be made as a measuring device for the liquid level (3, 4) in a container (1) of an electrically heated resistive conductor which has temperature-dependent resistance coefficients and whose resistance is measured by a bridge circuit (12). In this arrangement, resistive conductors (8, 10) having a positive temperature coefficient, and resistive conductors (9, 11) having a negative temperature coefficient are connected alternatively in series as a chain (7) in one bridge arm (7), and a plurality of such chains (7) are arranged adjacent in the vertical direction in the container (1), so that the mutually offset resistive conductors produce measured values which can be evaluated digitally. The invention serves, in particular, for determining the liquid level in the reactor pressure vessel (1) of a nuclear reactor.

Device for conversion of non-electrical quantity into electrical signal

Abstract: Device for conversion of a nonelectrical quantity into an electrical signal comprises measuring and compensating bridge circuits whose supply arms are connected to a power supply. A nonelectrical quantity like strain, force or pressure acts on the input of the measuring bridge circuit whose output is coupled to the input of a measuring circuit. The effect of destabilizing factors, such as temperature, electromagnetic field or aging of device components, is reduced by a suitable compensating bridge circuit whose output is connected to the input of a correction circuit. The measuring bridge circuit is one arm of the compensating bridge circuit. The correction circuit has differential outputs coupled to adjustable dividers whose number is equal to the number of compensating couplings introduced. Outputs of the dividers are connected to a displacement unit and to a device functional characteristic scaling circuit. The device also comprises an adjustable bridge circuit to compensate nonlinearity of the device functional characteristic and a unit for changing the steepness of said functional characteristic.

Circuit for transmitting energy to and from coils

Abstract: A circuit for transmitting energy to and from coils is improved by connecting a coil to a bridge circuit composed of a diode and a switch such as a gate turn-off thyristor. An opposite polarity switch and diode construction may be used in addition to selectively allow the direction of current flow through the coil to be reversible.

Constant temperature anemometer

Abstract: A constant temperature anemometer wherein a bridge circuit having four legs includes a sensor in one leg and resistances in the other legs. The resistance of two of the legs is formed, at least in part, by a potentiometer which allows a simultaneous adjustment of the resistance of those legs and, accordingly, the ratio of those resistances. The potentiometer may be selectively connected within the bridge circuit or, alternatively, with other circuitry to determine the operating resistance of the sensor.

Semiconductor acceleration sensor

Abstract: PURPOSE: To miniaturize and lighten the titled sensor, and to eliminate effects due to the residual strain of an adhesive layer and a creeping and improve reliability by constructing a cantilever by a single crystal silicon base body and diffusing and forming a strain gage into the base body. CONSTITUTION: When acceleration (G) is applied at the free end of a cantilever 1, strain is generated in the flexible section of the cantilever 1, the resistance values of each resistor R1, R2, R3, R4 as a strain gage 2 change in proportional to the magnitude of acceleration by a piezoresistance effect, and unbalanced voltage ΔV is generated as a bridge output by previously pplying voltage (E) to a bridge circuit. The rates of resistance (ΔR/R) of each gage are represented by ΔR/R=A.M.G/h 2 . When h is the thickness of a thin section 3, A a constant, M the thickness of load 5 and G the magnitude of acceleration. Intrinsic vibration frequency can be set to an arbitrary value within a predetermined range by adjusting the numerical values M, h of the load 5 and the thin section 3. COPYRIGHT: (C)1984,JPO&Japio

Transmitter of magnetic signal

Abstract: PURPOSE:To remove the effect of hysteresis, by constituting a circuit of a receiving side with a bridge circuit of magnetoresistance effect elements and a circuit at a transmission side with a coil energizing the bridge circuit and a current controller controlling a current flowing to the coil. CONSTITUTION:The energized circuit with the coil L at the transmission side is generated, a current flowing to the coil L is controlled with the current controller 3 and a signal is inputted to the controller 3 through an input section 4. On the other hand, plural magnetoresistance effect elements are arranged in prallel with each other in the circuit of the receiving side, and the elements form the bridge circuit B. Further, the output of the circuit B is transmitted to an amplifier A, the amplified signal is given to a switching circuit 5, where the signal is compared with a reference voltage, and the output is applied externally through an output section OT.

Apparatus for matching FET switches as for a video digital-to-analog converter

Abstract: A digital-to-analog converter includes a plurality of pairs of complementary conductivity field-effect transistors (FETs) coupled for applying reference potentials to a resistive ladder network in response to the bit values of an input digital word. A variable voltage generator develops gate biasing voltage for the FETs of one conductivity. The biasing voltage has a magnitude controlled in response to a bridge circuit including a further pair of complementary conductivity FETs also coupled to the reference potentials. As a result, the complementary conductivity FETs are automatically caused to exhibit matched conductivity characteristics.

Induced-signal capacitance effect cable tracking sensor

Abstract: Inductive coupling of a high-frequency signal into a cable to be detected d tracked in a seawater medium for sensing the relative position of the cable with respect to capacitor plates. The capacitor plates are positioned so that in conjunction with the cable a differential capacitor is formed. Relative movement of the capacitor plates with respect to the position of the cable is used to unbalance a Wheatstone Bridge circuit. The output signal from the bridge circuit is proportional to their displacement and is used to provide a guidance signal to realign the capacitor plates and the cable.

Method and apparatus for measuring normal line direction of surface of object

Abstract: PURPOSE:To measure a normal line at the contact point of a three-component force detection probe and an object to be measured, by calculating the repulsive force direction generated when the three-component force detection probe is pressed to the object to be measured. CONSTITUTION:A three-component force detection probe 1 capable of detecting forces in directions (x), (y), (z) is pressed to an object 2 to be measured. A positional determination apparatus 3 changes the positions of the three-component force detection probe 1 in directions (x), (y), (z) and the posture thereof around a y-axis. The three-component force detection probe 1 consists of a base 4, a leaf spring 5, an elastomer 6 and a probe needle 7 and two strain gauges 8 are adhered to the leaf spring 5 so as to make the centers thereof symmetric. Further, two strain gauges 9 are adhered to the elastomer 6 at a part becoming thin in an x-direction while two strain gauges 10 are adhered at a part becoming thin in a y-direction. By connecting strain gauges 8-10 to a bridge circuit, components in directions (z), (x), (y) acting on the probe needle 7 can be indenpendently detected by the strain gauges 8-10.

Method and circuit for generating drive pulses for a DC control element

Abstract: Method and circuitry for generating drive pulses for a DC control element of the type having four semiconductor switches arranged in a bridge circuit. Two triangular voltage waveforms are formed and are shifted with respect to one another by a difference voltage. Each bridge branch of the bridge circuit is driven in response to a comparison between the first triangular voltage waveform and a control voltage, and a second semiconductor switch of each bridge branch is driven in response to a comparison of the second triangular voltage waveform and the same control voltage. A pause between the conductive periods of the semiconductor switches within a bridge branch is obtained by driving the semiconductor switches with offset triangular voltage waveforms. The pauses prevent short circuits of a supply voltage source, and their duration is determined by the difference voltage and can therefore be achieved accurately at low cost.

Device for input stage of amplifying circuit

Abstract: PURPOSE:To eliminate the nonlinearity and to improve both the linearity and the working speed of a circuit, by selecting the value of a proper electronic means such as a resistance connected to an electrode of different electronic means at a proper level. CONSTITUTION:The transistors (TR)Q1 and Q2 from a complementary circuit, and the collector current of the TRQ2 is virtually a linear function of the input voltage to be applied to the base of the TRQ1. The TRQ3, TRQ4 and the resistances R2, R3 form a bridge circuit, and the gain of this bridge circuit is set by the ratio between the resistances R2 and R3. The degree of the positive linerity is set mainly be selecting the value of the R3 at a proper level. A circuit consisting of a TRQ5 and a resistance R4 functions completely as a linear current voltage converter.

Electronic capacitive measuring head for distance measurements

Abstract: A special electrode arrangement is adopted in a capacitive measuring head for the purpose of temperature stabilisation. An electrode arrangement (12, 13) which serves as a sensor is provided in a bridge circuit (3-7). A similar electrode arrangement (15, 16) in another (7) arm of the bridge circuit (3-7) serves the purpose of temperature compensation. The two electrode arrangements (12, 13; 15, 16) are arranged on the two sides of a common insulating plate (11) in order to guarantee good thermal contact.

Four-quadrants final control element for controlling a collectorless direct current machine.

Abstract: The invention relates to a four-quadrant final control element for controlling a collectorless direct current machine. The four-quadrant final control element has a commutating device consisting of semiconductor switching elements (1 to 6) arranged in a bridge circuit, to which commutation device are connected the winding strands (7 to 9) of the stator winding of a direct current machine. A rectifier bridge (11 to 16), likewise connected to the stator winding of the direct current machine, is connected in anti-parallel to the semiconductor switching elements. The one d.c. voltage pole of the rectifier bridge is connected directly to the corresponding input pole (-) of the four-quadrant final control element. A storage capacitor (20) is located between the two input poles (+ and -) of the four- quadrant final control element. In order to be able to recover as great a proportion of the braking energy as possible, it is provided that a semiconductor switching element (17), which can be periodically triggered and driven, is connected to both d.c. voltage poles of the rectifier bridge (11 to 16) and that the connection point (18) of the semiconductor switching element (17) is connected to the other d.c. voltage pole of the rectifier bridge (11 to 16) via a decoupling diode (19) on the other input pole (+) of the four-quadrant final control element.

Heat detecting arrangement

Abstract: The heat detector consists of a bridge circuit including two temperature dependent components 1 and 2, one of which is arranged to respond more quickly than the other to increase in the temperature of a region being monitored The components 1 and 2 are thin/thick film resistors directly deposited or provided in chip form on the longitudinal extremities of a long, thin substrate 3 formed of alumina The substrate 3 carries on its surface two resistors, 4 and 5, of fixed resistance, which are interconnected with elements 1 and 2 in known manner In an alternative arrangement substrate 3 is a printed circuit board supporting discrete components and providing a thermal gradient there-along Additional electrical components 6, active and/or passive in nature, are provided on the substrate 3 to respond to the output signals from the bridge circuit when a temperature and/or rate of temperature rise is exceeded to produce alarm and/or other activation signals

Heater temperature control circuit for air fuel ratio sensor

Abstract: PURPOSE:To prevent the generation of a rush current by raising a reference voltage according to a prescribed time constant when a power source is turned on. CONSTITUTION:A heater 4 and resistance 11-13 form a bridge circuit, and a power transistor (TR) 10 is controlled with the output of a differential amplifier 14 to control the heater 4 to fixed temperature. In this case, resistances 17-19, a capacitor 20, and a diode 21 are provided centering on a TR16 for control, and the rush current in power-on operation, etc., is suppressed. When a voltage is applied to a power source terminal 15, the capacitor 20 begins to be charged with a time constant tau determined by a resistance 19, and the base voltage of the TR16 varies following up it. This variation is transmitted to a differential amplifier 14, whose reference voltage is raised according to the time constant tau. Consequently, the current flowing to the heater 4 through the TR10 also increases from zero after the power-on operation according to the time constant tau.

Load receiver with deformable parallelogram

Abstract: The invention relates to a load receiver comprising a deformable parallelogram formed from a one-piece structure and a load transducer for detecting the deformation of the parallelogram under the effect of the applied load. The transducer comprises four series of pretensioned strain-gauge wire windings, each arranged obliquely between the two uprights (12, 16) or between the two arms (20, 22) of the parallelogram, so as to form two series of windings (34), the main strands of which are tensioned, and two series of windings (36), the main strands of which are compressed under the effect of the applied load, the four series of windings being connected in an electrical bridge circuit. The invention is used for commercial balances.