Abstract: An EGR control system provides on-line adaptation of the EGR valve Start to Open value during normal vehicle operations. The adaptive logic determines whether the valve position output signal reaches a predetermined minimum output signal value within a desired predetermined time window defined by upper and lower time values. If outside the window, the initial duty cycle value applied to the EGR valve is increased or decreased as appropriate to force the output signal to reach the minimum value within or at the boundaries of the time window.

Abstract: A varying voltage is applied across a coil of a contactor. The varying voltage has a characteristic (frequency) which varies as a function of the position of the armature. The varying voltage is transmitted to a coupler which transmits information to a controller. The coupler may include one or more light sources (LEDs) which are sequentially energized and de-energized to sequentially render a phototransistor conducting and nonconducting. The frequency of the output from the coupler corresponds to the frequency at which the phototransistor is changed between the conducting and nonconducting conditions. A controller determines whether the frequency of the output from the coupler corresponds to the intended position of the armature of the contactor or to an unintended position by comparing the frequency of the output from the coupler to known frequencies for various positions of the armature.

Abstract: An apparatus for making permanent magnet material magnetizes a body of material including a primary winding which has portions wound on a first core carrying current in a first direction creating a first field of flux and a secondary winding having portions wound on a second core wherein the secondary winding carries current in a second opposing direction to create a second field of flux. Since the currents are flowing in opposing directions, the secondary field of flux is directed to oppose the first field of flux. The result of this is that the magnetizer is capable of controlling the width of the pole to pole transition region for matching the stator geometry and thereby nearly eliminating cogging torque and reducing ripple torque.

Abstract: A bridge circuit, intended for use as a PWM driver of an inductive load, includes at least one source driver transistor connected in series totem-pole fashion with a sink driver transistor. A base resistor is connected from base to emitter of one of the driver transistors. This totem pole circuit is connected across a pair of DC supply conductors. A protective fly-back diode is connected across the one driver transistor. An auxiliary resistor is connected from the base of the auxiliary transistor to the emitter of the one driver transistor. When a fly-back diode across the one driver transistor conducts, the one driver transistor tends to conduct in the reverse direction and to store charge that in a subsequent period leads to shoot-through currents through the source and sink drivers.

Abstract: A power control circuit for replacing a current limiting fuse in an electrical protection circuit or for switching large currents rapidly has an array of transistors, each having an identical characteristic to each other and to a device under test, to provide parallel current paths. All of the rows of the transistor array are biased "on" except for a predetermined row. A gate signal is generated to control the "on/off" state of the transistors in the predetermined row, the gate signal being a function of the presence of excessive current--holding the predetermined row of transistors biased "on" in normal operation, and turning the predetermined row of transistors "off" when excessive current is detected.

Abstract: An electronic fuel injector driver circuit is a high speed operator of electromagnetic fuel injector valves for internal combustion engine. The drive circuit includes a solenoid coil for each electromagnetic fuel injector. A one shot timer circuit sends a predetermined timing signal to a first controller circuit interconnecting the one shot timer circuit and the solenoid coil wherein the predetermined timing signal is used to control the high side of the solenoid coil. A second controller circuit is connected to the solenoid coil and controls the low side of the solenoid coil in response to the predetermined timing signal. A switchable voltage reference circuit is connected to the second controller circuit and controls current through the solenoid coil.

Abstract: A latching relay control circuit comprising a latching relay pulse generator circuit and a relay coil drive circuit, the latching relay pulse generator circuit receiving relay control signals and relay reset signals. When a relay control signal changes states, the latching relay pulse generator provides a pulsed signal to the relay and coil drive circuit, the relay and coil drive circuit then changing the state of a latching relay. The relay reset signal is provided during power-up or just before power is lost to the system, the relay reset signal being provided to the latching relay pulse generator circuit wherein the latching relay pulse generator circuit provides a reset signal to the relay and coil driver circuit, and the relay and coil driver circuit opens all of the latching relays it controls.

Abstract: A system and method for operating high speed solenoid actuated devices such as electromagnetically operated high pressure fuel injectors require an initial high power boost to start the movement of an armature followed by a medium power boost to continue the movement of the armature to its end position and a low power control to hold the armature at its end position so that when the power is removed, the armature returns to its rest or beginning position. The system here details the logic and control necessary to provide six stages of power control, including both voltage and current control, to accomplish high speed operation both in moving the armature from its beginning to end position but also to return the armature from its end to its beginning position.

Abstract: In the case of a method and a device for triggering an electromagnetic consumer (1), which is connected in series to a switching means (2), the voltage applied to the switching means (2) is fed to a voltage comparison means (12) and compared there to the voltage of a reference voltage source (13). Dependent upon this voltage comparison, an output signal is produced at the output terminal of the voltage comparison means (12), which serves to switch over a suppressor device (4).

Abstract: An apparatus for suppression of individual ignition events in an ignition system includes a short-circuit switch, connected in parallel to the primary winding of the ignition coil. The short-circuit switch is controlled by a control switch. In order to avoid having to provide a separate power supply to furnish triggering energy to the control switch, this energy is derived from the energy stored in the ignition coil during a closing phase of the ignition switch. This requires fewer components than prior art circuits designed for the same purpose.

Abstract: An apparatus for energizing the coil of, and detecting the resultant armature actuation in, a solenoid of the type having a movable armature reciprocable along an axis between first and second positions, a spring bias normally biasing the armature toward the first position, and an actuating coil for inducing a force on the armature tending to move the armature from the first position toward the second position in response to current flow in the actuating coil. A voltage is first provided to the solenoid coil and thereafter, a resulting current flow is differentiated and a zero crossing comparator is utilized to determine when the differentiated current is zero and, therefor, the time at which the sensed current flow reaches a maximum (dv/dt=0). The time at which the armature began to move in response to the resulting coil current may be inferred and the voltage to the solenoid coil interrupted a Predetermined time after the time at which the armature began to move.

Abstract: A transformer isolated circuit for driving a semiconductor power switch includes a transformer which is driven with a high frequency Pulse Width Modulated (PWM) signal in such a way that the constantly present PWM carrier supplies the power needed for high gate current pulses, while different duty cycles determine the "on" or "off" state of the power device under control. Transformer saturation is prevented by sensing primary current and returning it to zero once per PWM cycle. Because of the high PWM carrier frequency used, the average transformer power is low, yet the secondary side is able to deliver high pulse currents for fast "on-off" switching of the gate of even the largest N- or P-channel device, without need for auxiliary power supplies. Also included are provisions for extremely fast output current limiting, for use where short circuit protection is necessary. Discussion of a monolithic implementation is included.

Abstract: In order to automatically restore a normal switching position of a relay armature from an accidental OFF switching induced by external impact or the like, the output of the relay is monitored and is applied to a differentiating circuit. A comparator is provided to reflect on and off operations of a main switch. In the event that the output of the relay falls suddenly, the differentiating circuit outputs a pulse to a wave-shaping circuit (e.g., Schmitt trigger). A gate circuit is supplied with the outputs of the wave-shaping circuit and the comparator. The output of the gate circuit momentarily allows a relay driver to actuate the relay in response to the undesired change in relay status, and hence the relay armature resumes ON switching position.

Abstract: A driver circuit that is responsive to an input AC voltage provides a variable drive signal to a load circuit, such as, a solenoid coil, for each actuation of a switch where the variable drive signal duration is determined by the setting of a variable resistor. In one embodiment, a sine wave shaper produces a positive edge variably delayed square wave timing signal for a continuously clocked flip-flop. In response to the switch actuation, the clocked flip-flop generates a control signal for a selected period of time that is related to one cycle of the AC input voltage. In another embodiment, a one shot produces a positive edge variable delayed square wave timing signal in response to the switch, the signal then being received by another one shot which creates a control signal for a selected period of time that is related to one cycle of the AC input voltage. The selected period of time occurs only during the positive portion of the input AC voltage cycle.

Abstract: A driver circuit that is responsive to an input AC voltage provides a variable drive signal to a load circuit, such as, a solenoid coil, for each actuation of a switch. A sine wave shaper produces a positive edge variably delayed square wave timing signal for a continuously clocked flip-flop. In response to the switch actuation, the clocked flip-flop generates a control signal for a selected period of time that is related to one cycle of the AC input voltage. The selected period of time occurs only during the positive portion of the input AC voltage cycle. The control signal is employed to generate the drive signal for the load circuit. The driver circuit provides switch bounce rejection equal to one cycle of the AC input voltage.

Abstract: In a printing device employing a solenoid for driving a printing hammer, provided are switching member for ON/OFF operating electric current flowing through the solenoid coil, voltage generating member for generating voltage in accordance with the electric current, converting member for converting the generated voltage to a digital value, chopping member for comparing the converted digital value with a predetermined comparison value, while for turning on the switching member when the converted value is smaller than the predetermined comparison value and turning off the switching member when the converted value is larger than the predetermined comparison value, another chopping member for alternatively turning the switching member in another predetermined interval shorter than the predetermined interval, when the set value becomes similar to the comparison value, during said predetermined interval.

Abstract: A print head activation circuit for a wire dot printer includes a first switch and a second switch. A CPU produces a printing timing control signal. A first driving signal-generating circuit produces a first driving signal pulse having a pulse width T.sub.1 in response to the printing timing control signal. A delay circuit delays the first driving signal. A second driving signal-generating means produces a second driving signal pulse having a pulse width T.sub.2 in response to the leading edge of the delayed first driving signal. The first switching means is connected with a DC power supply. The first switching means is also connected with one terminal of each actuator coil of the print head. The second switching means is connected between a second terminal of the actuator coil and ground. The second driving signal-generating means is operated in response to the delayed first driving signal. The delay time .DELTA.

Abstract: A single coil magnetic latching relay drive circuit which utilizes AC power for energizing/deenergizing the relay. To energize the relay, a single full half cycle of the AC power at a first polarity is applied to the relay coil. To deenergize the relay, a portion of a half cycle of the AC power of the other polarity is applied to the relay coil, this portion being chosen so that the effective current at the other polarity is insufficient to reenergize the relay.

Abstract: An apparatus for controlling a valve driven by electromagnetic force is adapted to sense the amount of bounce of a valve when the valve is seated, whereby a force in the valve seating direction is applied to the valve immediately after it is seated, thereby controlling the bounce force in accurate fashion. The apparatus is provided with memory means for storing the driving force applied by drive control means, and arithmetic means for deciding, in accordance with the driving force stored in the memory, a force acting in the valve lifting direction until immediately before the valve is seated, and a force immediately after the valve is seated. Control of driving force conforming to conditions such as engine rotation is thus learned so that the proper deceleration control can be performed at all times.

Abstract: A driving apparatus for a wire-dot print head in a wire-dot impact printer has a sensor mounted in the print head to detect the motion of the print wires, enabling each print wire to be driven for the optimum time for each dot. Beneficial results include improved print quality, reduced power consumption and operating temperature, and faster printing.

Abstract: The invention provides a device for controlling an electromagnet having a coil (L) connected to a monoarch periodic current supply source, through a controllable switch (TH). This switch (TH) is controlled by a control circuit comprising a member for detecting the zero cross-over times of the voltage of the source (R.sub.3, D.sub.4, IN.sub.1, R.sub.4, C.sub.3) and a switching device (FC) controlled by said detection member for delivering a closure signal to the switch (TH) following detection of a zero cross-over time which follows the order for controlling energization of the coil (L). The invention applies particularly to contactors and electromagnetic valves.

Abstract: In a relay circuit, a stationary contact of a relay is coupled to a DC voltage source and a moving contact of the relay is coupled to a load circuit. The moving contact is switched to the stationary contact in response to a rapidly rising edge of a DC voltage applied to the relay. A voltage sensor is connected to the moving contact for detecting a voltage which appears thereat. For operating the relay, a switch is closed to apply a voltage from the DC voltage source to a pulse generator. The pulse generator generates a rectangular pulse and applies it to the relay to cause it to switch the moving contact to the stationary contact. If a voltage is not detected by the voltage sensor at the moving contact after energization of the relay, the pulse generator reapplies a rectangular pulse to the relay until a voltage appears at the moving contact, whereupon the pulse generator applies a constant voltage to the relay.

Abstract: A solenoid driver system drives a solenoid, such as a solenoid in a glue applicator or any like apparatus incorporating a solenoid, and which requires control of the solenoid in response to a signal voltage. The solenoid driver system generates a turn on signal that enables the solenoid, such as that of a glue gun applicator, to energize quickly because of a rapid rise solenoid signal. A solenoid driver stage of two switching transistors and two high voltage fast recovery diodes are connected to a control pulse through a high side optical isolator and a high side buffer, and a low side optical isolator and a low side buffer. The low side circuit includes a trigger circuit and a delay circuit connected to a gate along with a free-running oscillator for periodically energizing the low side drive of the circuit in a mode as long as the input signal is energized. This ensures that the amount of current dissipated in the solenoid coil is small.

Abstract: The invention provides a device for controlling an electromagnet having a coil (L) connected to an AC supply source, through a switch (T) controlled by a control circuit.This control circuit comprising a member for determining the voltage zeros of the AC current (R.sub.4, C.sub.3, D.sub.3, IN.sub.1, C.sub.4, R.sub.6, IN.sub.2), a delay element adjusted for obtaining a delay time which corresponds to the privileged control angle of the electromagnet and a switch-over device (FL) controlled by the delay element for delivering to the switch (T), following a control order, a control signal delayed by said delay time. The invention applies particularly to contactors and electromagnetic valves.

Abstract: In a drive circuit device for an inductive load, the inductive load and a detecting resistor are incorporated in a current supply circuit in series relation to a drive transistor. An operational amplifier is operative in response to detecting voltage fed-back from the detecting resistor, for controlling the drive transistor, in turn, for controlling supply current flowing through the inductive load to a predetermined value. Turning-on and -off of the drive transistor are controlled by a switching element operative in response to a control signal, thereby carrying out current supply to an inductive load and stoppage of the current supply. A feed-back circuit is provided, in which a response element supplies feed-back current to be controlled by the operational amplifier, to the feed-back resistor, in response to the turning-off of the drive transistor. The operational amplifier carries out feed-back control without being saturated, even at the stoppage of the current supply to the inductive load.

Abstract: A recording apparatus in which recording on a recording medium is perfomed by impacting against the recording medium. This recording apparatus has a recording unit which is constututed by a recording element supported so as to be reciprocatively movable relative to the recording medium, an electromagnet for generating a magnetic force which makes the recording element impact against the recording medium on the basis of a recording signal, a detection coil for detecting the magnetic flux generated by the electromagnet, and a controller for controlling, on the basis of the results of detection supplied from the detection coil, conditions under which the electromagnet is driven.

Abstract: A switching circuit is suggested for controlling the current through an electrical consumer, in particular an electromagnetic consumer (10), whereby a field effect transistor (11) is used as a control and current measuring member being series connected to the consumer. The field effect transistor is brought into the conductive condition with the assistance of a controlling device, such as an operational amplifier which in turn is immediately controlled by switching-on enforcing means when the field effect transistor is short-circuited with respect to a power source. The switching-on enforcing means comprise a capacitor, for example.

Abstract: An improved solenoid driver control circuit is disclosed in which solenoid current is sensed and provided as an input to a comparator means comprising two separate comparators (24, 25). The comparator means receives a solenoid current sense signal (45) and maximum and minimum reference threshold levels which determine maximum and minimum current limits (I.sub.max, I.sub.min ; H.sub.max, H.sub.min) for solenoid current during initial pull-in excitation and subsequent hold excitation. Pull-in time (T.sub.1) is defined by a monostable multivibrator (33) reacting to a control pulse (41) to produce a predetermined pull-in time pulse (43) such that the pull-in time is independent of sensed solenoid current. During pull-in time a boost driver switch (53) applies high boost voltage to a power source terminal (16) which supplies solenoid current, and in response to achieving the maximum pull-in current limit (I.sub.max) lower battery voltage is provided at the power source terminal.

Abstract: In an injector for intermittently injecting liquid fuel by supplying a pulse signal to an actuator and reciprocating an injector valve, a method of controlling the injector valve comprising the steps of temporarily cutting supply of a pulse signal to the actuator to suppress inertia of the injector valve and thereby stabilize opening characteristics of the valve just before full opening of the valve during an opening stroke of the valve, and temporarily supplying the pulse signal after the cutting step of the pulse signal to the actuator to suppress inertia of the injector valve and thereby stabilize closing characteristics of the valve just before full closing of the valve during a closing stroke of the valve.

Abstract: A remotely controlled circuit breaker or switch comprises two breaking poles adjoining a remote control unit with an electromagnet, and a toggle for manual operation of the contacts. The remote control unit comprises a selector switch for switching into the electronic circuit a position detector of breaker contacts, four connection terminals, and an electronic power supply circuit for an electromagnet. Two of the input terminals TL (inpulse relay mode) and CT (contactor mode in the active position of the selector switch), are accessible simultaneously with the existence of a priority code between the two controls and of a refresh function of the statuses of the electronic circuit. The latter allows forced manual operation by means of the toggle.

Abstract: There is disclosed an improved drive circuit for a print element actuator wherein the current applied to the actuator has a fast rise mode which is terminated when a predetermined level has been reached. Current is allowed to slowly decay through the circuit until it reaches a second and lower predetermined level. The circuit is self-timing and self-compensating for variations in voltage or actuator impedance.

Abstract: A power supply/sink for use with switched inductive loads includes a transformer with a first secondary winding for generating power supply current connected in a circuit with a power supply terminal. A second secondary winding is connected in a circuit to a power sink terminal. The two secondary windings are interconnected with a controlled conduction path which is arranged to supply sink current in response to variations in the voltage at the power sink terminal.

Abstract: A solenoid drive system includes a driver circuit which functions to gradually increase current flowing through a solenoid coil. The attracting force created by the solenoid is proportional to the current flowing through the solenoid coil. When the attracting force becomes greater than a load including the plunger, the plunger moves toward the operating end. At a time when the plunger reaches the operating end, the current is still in the increasing curve and, therefore, an excess force is minimized. This functions to minimize noises created by the plunger movement.

Abstract: A relay control system is disclosed for alternately energizing and deenergizing a non-latching relay in response to successive applications of an AC impulse control signal to a control signal input. An impulse processing circuit converts the AC impulse control signal into a DC pulse. The DC pulse toggles a first flip-flop. The output from the first flip-flop is gated through a second flip-flop in response to a clock signal produced by an AC zero-crossing detector to synchronize the second flip-flop output with zero-crossings of the AC power signal. The output from the second flip-flop operates driving circuitry which energizes and deenergizes the relay coil, thereby toggling the relay. A power up reset circuit deenergizes the relay in response to the initiation of the AC power signal and presets the logic circuitry so that the next impulse of the AC control signal will energize the relay.

Abstract: In a current driving circuit which supplies a two-terminal load with current to be inverted in accordance with input information, a current driving circuit according to the present invention comprises a load whose one-side terminal has its potential fixed, circuitry to supply a non-fixed side terminal of the load with a direct current, and circuitry to supply the non-fixed side terminal with a current having a magnitude double that of the direct current and a polarity opposite to that of the direct current, while switching it in accordance with input information. Owing to such construction, the number of terminals to be led out from the loads can be reduced, and a load current can be inverted at high speed. In addition, reliability can be enhanced because the assembling process is simplified.

Abstract: The invention relates to an electronic device controlling the electromagnet of a multiple operation electrical apparatus.The electromagnetic coil (14) is connected in series to a triac (25) regulated by a generator (32) associated with a monostable flip-flop (34) designed to supply a single pulse of time-length T at each order from a logic circuit (36). A selector (38) cooperates with each output S.sub.1, S.sub.2, S.sub.3 . . . of the logic circuit (36) to choose a predetermined mode of operation of the apparatus (10), particularly remote-operated switch, contactor, or ON-OFF mode.

Abstract: A method and apparatus for rejuvenating magnetic toner used in certain electrostatic copying machines. The used toner is placed in a container which is inserted in an air coil which is energized to produce a magnetic field which remagnetizes the toner. The coil is provided by mounting a hollow non-magnetic tube in a case and winding this tube with wire. A timing circuit energized by a momentary switch determines the length of time a magnetic field is applied to the toner being recycled.

Abstract: A protective control system is provided for stopping an engine-driven pump when a fault condition such as low oil level, low oil pressure or high temperature occurs in the engine. The protective control system includes an electric battery, a solenoid valve regulating fuel (or air) flow to the engine and energizable from the battery, an electronic circuit energizable from the battery for controlling the solenoid valve, and fault-sensing switches for controlling the electronic circuit and shutting off the fuel supply to stop the engine upon occurrence of a fault. The electronic circuit includes a solid state voltage regulator device connected between the battery and the solenoid valve, and this device includes an adjustment terminal which is biased to control the power supply to the solenoid valve. The electronic circuit further includes a transistor which controls the bias on the adjustment terminal and the transistor, in turn, is responsive to operation of any one of the fault-responsive switches.

Abstract: A control circuit for a solenoid driver for a dispenser having inherent pull-in and drop-out delays. The circuit includes a tachometer that generates pulses representative of the speed of a conveyor that conveys a substrate upon which the dispenser dispenses fluid. A sensor generates a trigger signal indicating that the substrate is at a preselected location. Delay counter circuitry, enabled through the trigger signal, generates an enabling signal after receiving a preselected number of pulses. Duration counter circuitry, enabled by the enabling signal, generates an initial driving signal of a preselected signal duration. Compensator circuitry receives the initial driving signal and modifies it so as to compensate for the pull-in and drop-out delays so that fluid is deposited for the dispensing duration upon the substrate commencing at the preselected position.

Abstract: A fastener driving device such as a tacker, including an actuating circuit for producing a power stroke for substantially a complete half cycle of an AC potential supply and which occurs a fixed number of cycles following the actuation of a switch actuable at random times with respect to the cycles of the AC supply. The circuit features a decade counter clocked by the AC supply. One of the decade count outputs of the counter provides a signal for firing an SCR in series circuit with a solenoid for powering the tool. The counter is wired in circuit so as to latch at a predetermined count higher than the count output from which the firing signal is taken. Actuating the switch causes the counter to reset to zero, after which it counts positive half-cycles of the AC. When it reaches the count corresponding to the output from which the firing signal is taken, the tool is actuated. The counter continues to count until it relatches. It remains at the latched count until the switch is again actuated.

Abstract: A testable load driving circuit apparatus includes a solid-state load driver for controlling AC current loads coupled in series with a winding of a saturable core reactor used for sensing the presence or absence of load current through a load current monitor which is coupled to another winding in the reactor. The load driving circuitry may be tested during circuit operation by injecting a signal of insufficient duration to substantially affect the load circuit.

Abstract: The drive circuit for an electromagnetic actuator for the impact element in a printer includes a series circuit of a drive transistor and of a switching transistor there being a reference resistor interposed which together with a Zener diode serves as a current limiter for the current through the drive transistor and the electromagnetic element. The two transistors are controlled in that each of the base electrodes is serially connected to the emitter collector path of a control transistor and the two control transistors in turn are connected to monostable multivibrators which are triggered concurrently but furnish pulses of different duration such that the switching transistor is turned off before the drive transistor. The current limiting permits utilization of residual electromagnetic energy from the preceding actuation pulse without incurring undue losses.

Abstract: An embodiment of the present invention provides an excitation arrangement suitable for use in producing a pulse-shaped field of substantially constant intensity. To start-up the current at the beginning of a pulse, a coil (1) is fed with a high voltage (line 3) via an ignitable and blockable power semiconductor (7). For the duration of the pulse, switch-over is then effected to the supply of a lower voltage (line 4) by means of a power transistor (31) controllable to a constant current. Free-running diodes are used to decay the current. One coil end (2) is preferably connected via an FET (7) which is controllable to a constant voltage, to the high voltage; via an FET (30), which is likewise controllable to a constant voltage, to the lower-voltage (4); and via a controllable FET (52) to a reference line (6). Corresponding FET's (50, 51, 31) are provided at the other coil end (5).

Abstract: A solenoid drive circuit for a matrix printer comprises a capacitor (C1) connected in parallel with the series arrangement of a first diode (D2), the solenoid coil (L1), and the collector-emitter path of a transistor (T1). A second diode (D3) is connected in parallel with the coil (L1) and transistor (T1). The capacitor is charged from a d.c. supply which includes a switching regulator (10, T10) via a diode (D1). When the transistor is switched ON by a print signal applied to a terminal (4) the capacitor is discharged resonantly into the coil. The first diode (D2) prevents current flow from the solenoid to the capacitor during the negative half cycle of the resonant frequency so that current in the coil circulates in the loop formed by the coil, the transistor and the second diode. When the transistor is switched OFF the current flowing in the coil is discharged via a further diode (D4) into the storage capacitor (C10) of the d.c. power supply to increase the efficiency of the drive circuit.

Abstract: A drive circuit for a latching relay includes a flip-flop, a timer and a semiconductive switching circuit for the relay. First and second input signals are applied to the flip-flop and first and second control signals at the output of the flip-flop are applied alternately to the timer as a time limit output for controlling the energization of the switching circuit in concert with a high-speed changeover signal.

Abstract: An injector drive circuit in which the injector is opened in response to a pulse signal with a time width which determines the quantity of the fuel to be supplied to the engine. To the injector, a circuit for supplying a peak current at the time of fuel injection and a field effect transistor for supplying a holding current after supply of the peak current are connected in parallel. In response to the control signal from a fuel injection amount control circuit, the peak current is supplied to the injector, and upon detection that a predetermined peak current has been supplied to the injector, the peak current is stopped. Thereafter, by controlling the gate of the field effect transistor, the holding current is supplied to the injector through the field effect transistor, until the control signal is stopped.

Abstract: A comprehensive multiple rapper control system controls rapping intensity with enhanced accuracy, controls a large number of rappers in any desired sequence with intensity control for each individual rapper, and includes alarm circuitry for reliably indicating open circuited and short circuited conditions in the rapper coils or in the electrical connections to the rapper coils. For enhanced accuracy, a short boost pulse of full lift energy is applied immediately prior to a lift pulse of controlled energy. The boost pulse overcomes initial rapper plunger sticking forces so that total rapper plunger lift accurately reflects the electrical energy supplied during the subsequent controlled pulse. Advantage is taken of the relatively constant boost pulse which is supplied to every rapper in the system regardless of the energy supplied during the control pulse to provide an alarm circuit. Current through each rapper plunger lift coil is sensed during at least a portion of the boost pulse.

Abstract: In a circuit for controlling the current flow through a coil, such as the horizontal deflection coil of a television receiver, a first switching device including, for example, a first switching transistor and a first damper diode is connected in parallel with a first resonant circuit including a first capacitor and a first coil, which is the coil through which the current flow is to be controlled. A second switching device including for example, a second switching transistor and a second damper diode is connected in parallel with a second resonant circuit including a second capacitor and a second coil. First and second charging capacitors are connected in series with the first and second coils, respectively, and the power is supplied to the first and second resonant circuits for example through a third coil.

Abstract: A circuit provides means for driving a load under control of a plurality of signals including a drive timing signal which is given a maximum permissible duration by the circuit to prevent damage to the load, an operating signal, and an inhibit signal which prevents operation in case of excessively low power supply voltage. A power supply of opposite polarity is connected to the load so that the load rapidly dissipates its energy into said power supply at the time of turn-off of the drive circuit.

Abstract: A magnetic device comprising two permanent magnets, armature members forming with said magnets a closed magnetic circuit and an external air gap, and means for reversing the direction of magnetization of one of the magnets, whereby the flux is prevented to close along the magnetic circuit and caused to close through the air gap, or caused to close along the magnetic circuit, the flux in the air gap then being suppressed. The said means consist of two distinct coils wound about the magnets. One of the coils is energized for establishing the flux in the air gap, while the other coil is energized for suppressing the flux in the air gap.