Abstract: An opening/closing body drive device includes: a motor which opens or closes an opening/closing body; a drive unit which rotates the motor; and a control unit which controls the drive unit. The drive unit includes first and second integrated circuits having first and second switching elements and third and fourth switching elements which are connected to each other in series with respect to a power source and connection points of which are connected to one and the other terminals of the motor, respectively. The control unit turn-on drives only the second switching element when braking the motor during the forward rotation and turn-on drives only the fourth switching element when braking the motor during the reverse rotation, or turn-on drives only the third switching element when braking the motor during the forward rotation and turn-on drives only the first switching element when braking the motor during the reverse rotation.

Abstract: A control circuit includes a first high-side transistor coupled between a voltage supply terminal and the first terminal of a DC motor and a second high-side transistor coupled between the voltage supply terminal and the second terminal of the DC motor. The control circuit includes a first low-side transistor coupled between a ground terminal and the first terminal of the DC motor and a second low-side transistor coupled between the ground terminal and the second terminal of the DC motor. The control circuit includes a first pull-up resistor coupled between the voltage supply terminal and a gate terminal of the first low-side transistor and a second pull-up resistor coupled between the voltage supply terminal and a gate terminal of the second low-side transistor. The pull-up resistors apply bias currents to turn ON the first and second low-side transistors to provide a conductive path to brake the DC motor.

Abstract: A stringed musical instrument comprises a bridge that receives a plurality of strings. The bridge comprises at least one internal pocket. In some embodiments, the bridge comprises a plurality of internal pockets.

Abstract: A carbon fiber sound board is disclosed with breaks in the fibers to improve the sound quality and timber of the carbon fiber instrument.

Abstract: Gate driver circuit for driving power transistor includes: gate line to be connected to the transistor; source line to be connected to the transistor; first current source sourcing current to the gate line; and second current source sinking current from the gate line, wherein the first current source includes: first reference impedance element connected to power supply line; first reference transistor installed between the first reference impedance element and the gate line; first error amplifier having output connected to gate of the first reference transistor, one input connected to the first reference impedance element, and the other input where first reference voltage is input; and first transistor elements installed between the power supply line and the gate line, and wherein the first current source is switched between a state, in which gate of each first transistor element is connected to the output of the first error amplifier, and OFF state.

Abstract: One aspect of the present disclosure relates to an electric power tool including a motor, an operation unit, a bridge circuit, and a control unit. The control unit performs a brake control when the motor is braked, and performs a regenerative current inhibition control before stopping the brake control when a drive command is inputted to the operation unit while the brake control is performed.

Abstract: A ripple current sensing type motor controlling apparatus includes: an H bridge circuit switched depending on at least one control; a first resistor of which one end is connected to one end of the motor through the H bridge circuit and the other end is connected to a ground; a second resistor of which one end is connected to the other end of the motor through the H bridge circuit and the other end is connected to one end of the first resistor and is connected to one end of the motor through the H bridge circuit; and a controller calculating a RPM of the motor using a voltage across the first resistor in the case in which the driving power is applied to the motor and calculating the RPM of the motor using a voltage across the second resistor in the case in which the driving power is blocked.

Abstract: A method for operating an electric motor connectable via a switching device to a current source and connected in parallel with a freewheeling device, the switching device having control applied to it at a specific activation ratio within each working cycle to establish a desired effective operating voltage of the electric motor, so that in at least one operating mode each working cycle is includes an activation and a freewheeling time period. The freewheeling device has a freewheeling transistor and a freewheeling diode, connected in parallel with the transistor and reverse-biased as to the current source; and control is applied to the freewheeling transistor in the freewheeling time period as follows: identifying the freewheeling voltage dropping across the electric motor; and switching the freewheeling transistor for a specific switching time period if the freewheeling voltage is different from zero, particularly less than zero. Also described is an electric motor device.

Abstract: The present invention relates to an amplifier circuit, comprising: first to fourth semiconductor amplifiers for controlling first to fourth currents between supply and output terminals, a first input terminal connected to provide a first input signal to a first control terminal of the first semiconductor amplifier and to a fourth control terminal of the fourth semiconductor amplifier, and a second input terminal connected to provide a second input signal to a second control terminal of the second semiconductor amplifier and to a third control terminal of the third semiconductor amplifier. The present invention also relates to a bi-stage amplifier circuit, and to a multi-stage amplifier circuit comprising a cascade of a number of amplifier circuits complying to the present invention, the multi-stage amplifier circuit having a gain control logic prepared to control a gain of at least one of the amplifier circuits.

Abstract: Stepper motor winding current regulation methods and apparatus continuously and bi-directionally sense winding current to determine both the magnitude of the winding current and the slope of a waveform representing the winding current. The magnitude and slope information is used to more precisely control periods of current rise and characteristics of fast and slow current decay during pulse-width modulation (“PWM”) regulation cycles. Winding current rise and decay shaping is based upon the sensed magnitude of the winding current, the magnitude of the winding current regulation set-point ITRIP, whether the sensed winding current is greater than or less than ITRIP at a selected sampling time, whether the sensed winding current is increasing or decreasing when a waveform of the sensed winding current crosses over ITRIP, and whether or not the magnitude of ITRIP changes during a PWM cycle in response to a receipt of a subsequent DAC code.

Abstract: A controller for a DC motor comprises an output switching element configured to couple to the DC motor; an input switching element coupled to the output switching element; a pulse width modulated (PWM) signal coupled to a control terminal of the input switching element and a supply voltage applied to the output switching element. A resistive-capacitive (RC) network may be coupled to a control terminal of the output switching element, with the RC network being configured to integrate the PWM signal into a DC voltage. A first resistive network may be configured to set a bias for the output switching element when the input switching element is turned off, and a second resistive network may be configured to set the bias for the output switching element when the input switching element is turned on, such that the controller is effective to provide zero-to-full supply voltage control to the DC motor.

Abstract: An electric motor drive system capture and control apparatus for energy savings has an alternating current power source electrically connected to a direct current motor. A power rectifier diode rated for the alternating current power source and the direct current motor is electrically connected in a reverse bias mode between the negative supply wire of the direct current motor and a grounded neutral conductor of the alternating current power source. A ground wire is electrically connected to the direct current motor and cross connected to a hot lag wire of the alternating current power source. The direct current motor is voltage matched to the alternating current power source. A transformer is electrically connected to the alternating current power source and the direct current motor. The system may be scaled to work with a power grid or for use in a vehicle.

Abstract: An electronically commutated motor (20) has a rotor (28) and a rotor position sensor (30), which sensor, during operation, furnishes a rotational position signal (34). A stator interacts with the rotor (28). The stator has a stator winding strand (26) in an H bridge (22), and a control apparatus (36) which, during operation, performs the steps of: (A) controlling the H bridge (22) so that current pulses (+i1, ?i1) flow through the stator winding strand (26), in alternate directions, each pulse starting at a first point in time (t1); (B) at the beginning of each commutation, starting from a second point in time (t2), operating in short circuit the winding strand (26), in order to cause a decreasing loop current (I*) through the stator winding strand (26), which loop current (I*) reaches zero at a third point in time (t3); and (C) stepwise modifying, toward a minimum, the time interval (TCC) between the first and third points in time (t1, t3).

Abstract: A dispensing motor apparatus includes a motor assembly for driving a dispenser, the motor assembly having a motor. The dispenser is driven by the motor. One or more relays having electrical contacts can be integrated with the motor assembly. The motor changes its direction of rotation when its polarity is switched by relay(s). Additionally, a controller can communicate with the relay(s) and the motor assembly, such that the controller permits the relay(s) to switch the position of the contacts of the relay(s) before power is turned on with respect to the motor through the electrical contacts and switch the position of the electrical contacts of the relay(s) to a default state after the power is removed from the motor through the electrical contacts. The relay(s) is subject to mechanical cycling without the contacts of relay(s) being required to perform a current switching duty.

Abstract: A load drive control circuit for controlling a load that includes connection terminals. The load drive control circuit includes bridge circuits respectively connected to the connection terminals of the load. Each bridge circuit includes two semiconductor elements, which are connected between a power supply and ground, and an output terminal. The semiconductor elements are each controlled to be switched between activated and deactivated states. The output terminal of each bridge circuit generates a bridge output that varies in accordance with a combination of the activated and deactivated states of the semiconductor elements in the bridge circuit. A detection circuit detects whether a short circuit is occurring in the connection terminals. A control circuit switches the bridge circuits to electrically disconnect the load from the power supply when a short circuit is occurring during a period in which the load is in a suspended state.

Abstract: A control circuit for an electronically commutated motor (120), having a power stage (122) that comprises at least two semiconductor switches (216, 218) to influence the motor current. The semiconductor switches are controllable by way of commutation signals. The control circuit comprises a current measuring element (170) to make available a motor current control variable (I) dependent on the motor current, a base diode (240) that is arranged in series with the current measuring element and between the current measuring element and the at least two semiconductor switches, and a motor current setting element (180) with which the commutation signals can be influenced as a function of the motor current control variable.

Abstract: A circuit enables current to be measured in at least two motor leads of a three-phase motor being supplied by a power source generating a chopped sinusoidal waveform for the motor leads.

Abstract: A circuit is adapted to activate a writer head of a data storage media drive during both the boost periods as well as the steady state periods. The current supplied to the writer head during the boost periods exceeds the steady state current and flows between positive and negative voltage supplies so as to provide the required magnetic flux change in the inductor disposed in the write head. During the steady state periods, a switch circuit is turned on to provide a second current path across the writer head. During the steady state periods, the current flows between the positive voltage supply and the ground to reduce power consumption. The switch circuit is turned off during the boost periods.

Abstract: A soundboard for a hollow-body stringed instrument made of layers of carbon-fiber and resin material surrounding a core of one or more layers of constant-thickness plywood, veneer (thinly sliced wood) or paper. Additional shaped layers are provided to produce a desired pattern of stiffness in the soundboard. The soundboard may be tuned by attaching additional masses to a surface of the soundboard. A method of making and tuning the soundboard of the invention is provided.

Abstract: A method for driving a motor by imposing the current in the motor by means of power current mirrors is presented. This allows driving the motor in current with higher accuracy and lower electrical noise. The Hard Disk Drive application is an example where higher resolution is required for the VCM motor. Furthermore this method reduces the complexity of the system eliminating components and high performance circuits. Moreover this approach reduces the development and manufacturing cost by simplifying the testability and the analysis of the system. The intrinsic elimination of DC offset also takes out the need for the system offset calibration phase and significantly improves on the harmonic distortion of the transfer function. Furthermore this method offers the advantage of faster overall response of the system and higher efficiency.

Abstract: A rotation information detection device detects rotation information of a DC motor based on a surge component waveform superimposed on a voltage waveform between the terminals of the DC motor or a current waveform of the DC motor, a circuit is provided which supplies a current of a current value Ipwm 45% during motor forward rotation or Ipwm 55% during reverse motor rotation to the motor over the period from when the motor starts braking operation to when it stops.

Abstract: A pre-drive circuit for a brushless DC single-phase motor permits a cost reduction and an easy adjustment for the control input voltage of a switching device adjacent to a power source in a wider range, especially in increasing the control input voltage. In a drive circuit having four switching devices making up an H-bridge circuit with a motor coil being sandwiched therebetween, a control voltage exceeding a power supply voltage is required to turn ON the switching devices adjacent to the power source. The pre-drive circuit changes the duty ratio of the control voltage controlling motor speed. A circuit unit for generating pulse signals for controlling the switching devices uses an inexpensive logic circuit.

Abstract: A micro-motor position controller utilizes a ratiometric position sensor that operates independent of any reference voltage sources. A first capacitor and a second capacitor in a micro-motor are connected in series and form one section of a capacitive bridge. The other section of the bridge is ground. A first sinusoidal voltage is created at the top of the capacitive bridge and a second sinusoidal voltage that is 180 degrees out of phase from the first sinusoidal voltage is created at the bottom of the bridge. The motor is moved and the capacitance values of the first and second capacitors are changed until, ultimately, there is no voltage present on the armature of the motor. The voltage level present at the armature is measured relative to AC ground, and is used as an error signal to control the position of the motor.

Abstract: In order to brake a brushless motor in a forward rotation to give a reverse rotation force, source-side and sink-side transistors for supplying driving circuits *a, *b, *c, *d, *e, *f are periodically switched on and switched off based on the oscillation frequency of an oscillator (13) when a both end voltage of a current detection resistance (10) is higher than a reference voltage Vref. Moreover, the transistors are kept in an ON state all the time when the both end voltage of the current detection resistance (1) has lowered below the reference voltage Vref. With this arrangement, damage to a source-side transistor due to a large current flowing thereinto when the motor rotating in a reverse direction can be prevented.

Abstract: A motor drive circuit is comprised of an H-bridge circuit which is formed of a flywheel diode and a switching device and connected to a motor coil; a current detecting circuit which is connected to the H-bridge circuit, has a plurality of shunt resistors, and computes a motor coil current value on the basis of voltage drops in the shunt resistors; a memory for storing an energizing direction of the motor coil and command value data regarding an energizing current waveform; a control circuit issues energizing current amount of the motor coil so that an error between command value data stored in the memory and a detected current signal detected by the current detecting circuit always stays zero; and a switching device driving logic circuit switches both source and sink of the H-bridge circuit when the motor coil is excited.

Abstract: A travel-limit circuit having a DC motor for a lens by which the endurance of the motor can be improved while at the same reducing the rebound due to the inertia of the moving body at a travel extremity. The travel-limit circuit has a lens motor that drives, e.g., zoom lens groups. Limits which detect whether the lens group has reached their travel extremities at which mechanical stoppers are provided. The motor driving circuit, which drives the lens motor and the limit switches, activates a short break by short circuiting the pair of input terminals on the lens motor via diodes while cutting current flow from the motor driving circuit for the lens motor upon detection that the lens groups have reached their travel limit.

Abstract: A drive current and a regenerative current are alternately applied to a motor during a PWM (pulse width modulation) time period. The regenerative current is produced by an electromagnetic induction of an armature and flows in the opposite direction as the drive current. Therefore, a rotating speed of the motor is reduced, so that a speed-reduction following characteristic for the motor is improved. By varying the duty factor, the lengths of time during which the drive current and the regenerative current are flowing can be controlled. Thus, the speed of the motor can be controlled.

Abstract: A motor drive circuit 1 is driven by a DC power source 2 connected to power source terminals Tv1, Tv2 and has a first drive transistor Q1 for controlling a drive current supplied to a first terminal Tm1 of a motor from the DC power source 2, a second drive transistor Q2 for supplying current drawn from the first terminal Tm1 of the motor 3 to a ground, a third drive transistor Q3 for controlling a drive current supplied to a second terminal Tm2 of the motor 3 from the DC power source 2, a fourth drive transistor Q4 for drawing current from a second terminal Tm2 of the motor 3, a drive control circuit 4 for controlling the operation of the motor 3 by controlling the drive transistors Q1 through Q4 in response to a first and second control signal supplied to a first and second control terminal Tc1, Tc2, a first control transistor Qc1 having the same polarity as, and connected in parallel to and in the reverse direction of, the second drive transistor Q2 and a second control transistor Qc2 having the same polari

Abstract: A control apparatus for an electric power steering system assures stability of the feedback control and control generation of noise from the control circuit when the steering wheel automatically returns to the neutral position by means of the self-aligning torque in order to improve the feeling of the steering operation. In the motor driving circuit connecting four semiconductor elements in the shape of H bridge, the semiconductors of the first arm are driven by the duty ratio D1 while the semiconductors of the second arm are driven by the duty radio D2 defined by the function of the duty ratio D1 (D2 is longer in time than D1).

Abstract: A fluid valve has a housing formed by first and second halves which combine at mating surfaces to form a cavity with an inlet in the first half and an outlet in the second half. The mating surface of each half includes a notch extending between an outer edge of mating surface and the cavity, and includes an annular recess around the cavity. A pad is formed on each mating surface between the cavity and the annular recess, and has a groove that forms a bushing when the first and second units are connected. A butterfly valve member is located within the cavity and is mounted on a valve stem. The valve stem has an end that rides in the bushing and a portion that passes through the notches in the housing halves. An annular seal fits within the recesses to prevent fluid leakage between the two housing halves and also seals around the valve stem portion. In addition the butterfly valve member engages the seal in a closed state of the valve.

Abstract: A power steering apparatus for use in association with an electric motor, includes a switch circuit driven by a PWM wave signal which switches between one polarity and the other of the voltage developed across a motor-driving current detecting resistance synchronously with the PWM wave signal so as to detect the magnitude and direction of the motor-driving current, thereby controlling a duty cycle of the PWM wave signal in accordance with the detected motor-driving current. Thus, the motor steering touch and feeling is enhanced.

Abstract: A motor control circuit is used to generate positive and negative voltage supply rails. The motor control circuit contains two halfbridges, each of which contains a pair of MOSFETs connected in series, each of the MOSFETs being formed without the customary short between the source and substrate (body). In one embodiment, a common node between the MOSFETs is connected to a positive voltage supply rail, and the body regions of the MOSFETs are connected to a negative voltage supply rail. The positive and negative voltage supply rails are biased by charging respective capacitors, using the positive and negative voltage spikes that appear at the outputs of the motor control circuit as the outputs switch from a low state to a high state, and vice versa.

Abstract: In the transistor power output stages disclosed herein, short-circuit protection is provided with respect to output terminals through which a reversible motor or other load is to be energized. An output stage connected between the load and one of the supply leads provides current gain for energizing the load at a current level which is a function of the level of drive current provided to the output stage. Drive current is provided only at a first level independently of the voltage at the output terminal and a sensing means provides drive current at an increased level when the voltage at the output terminal is in a normal range, e.g. close to the voltage at the respective supply lead.

Abstract: A motor driving device is provided with switches connected with both terminals of a motor in an H-bridge connection and malfunction detectors connected with both terminals of said motor. The malfunction detectors are comprised of an impression part and a detection part which can detect the breakdown of the respective switches caused by open breakage or short breakage according to an output signal from the detection part corresponding to an input signal from the impression part.

Abstract: A logic-controlled circuit superimposes a constant voltage across an actuator or motor load that is driven by a bridge-type amplifier to control the constant velocity operation of such load in response to an applied logic signal that may also disable the bridge-type amplifier.

Abstract: A field installable motor operator for a circuit breaker includes a bidirectionally controllable motor that is coupled through a torque limited module to a circuit breaker operating mechanism. The motor is bidirectionally driven by a transistor switching bridge that supplies output current in reversible flow directions through one of the windings of the motor to the input of a rectifier bridge that supplies the other winding with currents that flow in the same direction. The torque limited module includes a centering and spacing ring which precisely confines the clutch elements to provide consistent torque. The motor is supplied with a current pulse of 250 milliseconds duration that is longer than the time required to fully operate the breaker. The clutch slips when breaker operation is completed and permits the motor to overrun without damage.

Abstract: Motor control systems are commonly associated with motors found on electric industrial vehicles, such as lift trucks. Advantageously, the control of such motors should be optimized such that current is timely supplied to the motors in conjunction with selection of the appropriate motor direction. The instant apparatus 10 includes a logic device 24 for receiving speed and direction demand signals from respective speed and direction selection devices 20,22. The logic device 24 responsively produces respective motor speed and direction command signals. A motor control device 26 receives the command signals and directs the electrical current from a power source 18 through the motor 12. A transducer device 38 senses the actual direction of electrical current flow through the motor 12 and produces responsive feedback signals. The logic device 24 produces at least one motor direction interrogation pulse in response to receiving the speed and direction demand signals and prior to delivering the motor command signals.

Abstract: A DC motor is connected across the mid-points of a bridge circuit which includes a switching device in each leg of the bridge. A forward or reverse motor direction drive current flows through the motor depending on the conducting states of the switching devices. A motor drive control device operates to produce either forward or reverse drive signals for controlling the conductivities of the bridge switching devices to thereby produce a forward or reverse motor direction drive current in response to a forward or reverse drive signal respectively. The drive control device detects and measures the level of the motor drive current and when it exceeds a predetermined target value, orders a gating circuit in the path of the forward and reverse drive signals, to invert the forward and reverse drive signals to thereby reverse the direction of the motor direction drive current. This produces a braking action. The gating circuit is preferably constructed of a plurality of EXCLUSIVE OR circuits.

Abstract: An MOS SCR and MOSFET "H" switch circuit for a DC motor is provided which allows for the use of a supply voltage of greater than 20 volts by clamping the gate-to-cathode voltage of the SCR's used therein to a predetermined value which is less than the gate-to-cathode breakdown voltage of said SCR's.

Abstract: An improved H-bridge power amplifier for controllably driving a dc motor is presented. The motor is connected in the center of the H-bridge in conventional manner. The H-bridge includes a current sense resistor placed between the power supply and a common tie point of the upper transistors of the bridge. Free wheeling diodes are connected from the motor directly to the power supply. This arrangement allows current to flow through the current sense resistor only when one of the upper transistors is on. The power amplifier is operated by selecting an appropriate pair of upper and lower transistors on opposite sides of the bridge so as to cause the current to flow through the motor in a desired direction. Both the upper and lower transistors of the selected pair are held ON until the current as sensed in the current sense resistor equals or exceeds a specified value, typically a desired current level.

Abstract: A solid-state electronic control system for an electric motor which drives a pipe bending machine. A machine operator's hand switch acts through a logic system to cause the motor to run in either direction, and negates control conflicts.The logic system controls an SCR bridge system to select the direction of D.C. energization of the motor for forward or reverse drive. This bridge system is supplied from A.C. mains through a bridge rectifier comprising three diodes and one SCR. When motor drive is called for, this SCR is made conducting to provide full-wave rectification. When motor drive is terminated, this SCR is turned off so that the rectifier becomes half-wave, which facilitates turn-off of the motor reversing SCR's.A dynamic brake for the motor is turned on by a triac when motor energization is shut off.

Abstract: A control for a vehicle window driving motor in an H-switch semiconductor bridge with an SCR and a FET in each opposite armature current path includes control logic circuitry enabling one-touch actuation of window movement in either direction with stoppage by actuating either actuation device and with flip-flop control of the bridge elements to prevent shorting out the power supply. A variation provides automatic stoppage in the up direction by stall current sensing with automatic reverse after a time delay to allow the SCR conducting during upward movement to turn off.

Abstract: A D.C. motor driving circuit comprises a first transistor circuit comprising an initial stage transistor and a terminal stage transistor respectively connected in Darlington pairs, for supplying a current to a D.C. motor, coupled between the D.C. motor and a power source, a switching transistor coupled to the initial stage transistor of the first transistor circuit, and a second transistor circuit including a transistor coupled in parallel to the first transistor circuit, for supplying a current to the D.C. motor. The switching transistor is turned ON when applied with a driving signal voltage to put the first transistor circuit in an ON state. The current supplied to the D.C. motor decreases as a rotational speed thereof increases after starting of the D.C. motor. The first transistor circuit is turned OFF when the rotational speed of the D.C. motor reaches a speed near its constant normal rotational speed. The D.C.

Abstract: A bi-directional driver system for an electrical load operable in response to two independent logic command signals provides a means for selecting the direction of current flow in the load when driven by the external command. A bridge circuit employs inputs to dual transistor switches operating in the saturated mode in series with the electrical load, cooperating with common emitter transistor linear amplifiers and diodes, and biased by the input logic signal so as to drive the load current in a predetermined direction. The circuit provides protection from undesired power supply current surges when logic command signals are applied to both inputs, and from transients due to failure of a saturated transistor switch at one input to cease conducting before the application of a command signal to the second input. Embodiments for inductive loads and annunciator lamps are described.

Abstract: A direction reversing apparatus for a rotary motor of a microcassette tape transport includes a motor (14) having substantially the same characteristic for the forward and reverse motor rotation directions for driving a recording tape, and a motor controller (12) for setting a motor speed to a given speed. The reversing apparatus further includes a switch (16) coupled between the motor (14) and the motor controller (12) for reversing the direction of rotation of the motor (14).

Abstract: An H-switch driver circuit includes two pairs of opposed drive transistors each pair being selectively energized to control the polarity of power applied to a load. Each pair of transistors is energized by a power current mirror that includes an NPN transistor that supplies base drive current to the remaining transistors in the power current mirror. The emitter of the NPN transistor is coupled to the load. The NPN transistor is biased off to inhibit base drive current to the circuit transistors in the event of a short to plus fault at one of the load terminals.

Abstract: A power amplifier is disclosed for controlling the current flow through a load, such as a d-c servo motor. The amplifier includes a plurality of switching elements connected in bridge fashion with the load and a predetermined power source for coupling the load across alternate output terminals of the power source in accordance with the levels of a plurality of control signals respectively coupled to the plurality of switching elements. Logic circuitry, when enabled, couples each of the control signals to their respective switching elements for controlling same. Sensing circuitry is coupled to the load for generating an actual current signal indicative of the actual level of current flow through the load. A current limiter is coupled to the sensing circuitry for comparing the actual current signal with high and low level limit signals and for generating a current disable signal when either the actual current signal exceeds the high limit signal or the low limit signal exceeds the actual current signal.

Abstract: In order to control the motion of a final control element, for example a servomotor used in the steering gear or the cruise control of a motor vehicle, and to provide for rapid dynamic braking of the servomotor by short-circuiting, the invention provides a bridge circuit consisting of four power transistors each of which is controlled by connection to one input transistor. The bases of pairs of input transistors are joined and receive control signals of equal or opposite values. The emitter of one transistor in each pair is joined to the emitter of another transistor in each pair and is then connected to respective supply lines of the circuit or to a source of an average supply voltage.

Abstract: Power control system comprising an intermittent device for applying intermittent voltage between intermittent voltage terminals; the intermittent device having a DC input terminal and at least one pair of intermittent terminals; a plurality of pairs of reverse series connected devices comprising control electrical valves and other electrical valves; said connected devices being connected in parallel between the intermittent voltage terminals; and a plurality of loads which are respectively connected to the series junctions of the plurality of pairs of reverse series connected devices.

Abstract: A motor control circuit of the Wheatstone bridge type is described for driving a direct current motor, selectively, in one direction or the other for the general purpose of automatically setting the diaphragm of a photographic camera in accordance with the light impinging on a photo-responsive element.