Abstract: A solenoid driver circuit includes an idling control portion for applying a very low voltage less than an activation threshold value to a solenoid from a switching circuit; a computing portion for computing the resistance value of the solenoid with the current value flowing through the solenoid and the applied voltage; and a constant-current control portion for maintaining the current flowing through the solenoid constant regardless of the temperature of the winding of the solenoid by controlling the output voltage from the switching circuit according to the resistance value. When the solenoid is activated, the supplied current is controlled constant irrespective of the temperature of the winding of the solenoid.

Abstract: A controller for an electromagnetic actuator is provided that enables detection of a minute movement of the armature leaving the seating position and carries out pullback operation responsive to such detection. The electromagnetic actuator has a pair of springs acting on opposite directions, and an armature coupled to a mechanical element such as a exhaust/intake valve of an automobile engine. The armature is held in a neutral position given by the springs when the actuator is not activated. The actuator includes a pair of electromagnets for driving the armature between two end positions. The controller comprises current supplying means for supplying holding current to the electromagnet corresponding to one of the end positions when holding the armature in said one of the end positions.

Abstract: Electrical energy is charged to a dielectric by using an energizing unit. A relay apparatus includes a first electromagnetic relay and a second electromagnetic relay. One light-emitting transistor is turned on by self-maintaining the second electromagnetic relay and, then, one light-receiving transistor is turned on. Another light-emitting diode is turned on by discharging the dielectric and another light-receiving transistor is turned on. A power voltage is applied to a base of a transistor for start, and the transistor for start is turned on. The first electromagnetic relay is self-maintained, an interval between output terminals is energized, and a load is driven. Accordingly, the relay apparatus can be miniaturized with a safety function and with low costs.

Abstract: An energy efficient multiple actuator control circuit is disclosed comprising a timing-slicing circuit for arranging and processing a pulsed select signal into a plurality of staggered pulse signals and a steering logic circuit for receiving the pulse signals and generating corresponding actuator enable signals. Latching solenoid actuators are arranged into position upon receipt of the pulsed actuator enable signals. The actuators maintain their position without any additional power. The circuitry is hardwired in that for a given select signal each actuator is activated into a predetermined position. The circuitry is scalable to arrange any plurality of actuators in any prearranged configuration, and the circuitry can perform properly over a broad variation of select signals.

Abstract: An electrical driver circuit for a cantilever solenoid valve includes first and second electrical switching devices for converting logical control input signals into respective control outputs. Third and fourth electrical switching devices are controlled as a function of the control output produced by the first switching device. Fifth and sixth electrical switching devices are controlled as a function of the control output produced by the second switching device. A voltage potential difference is created between a first electrically common point, defined between the third and fourth switching devices, and a second electrically common point, defined between the fifth and sixth switching devices, as a function of the logical signals received into the first and second switching devices.

Abstract: The control device comprises two power supply terminals and a local control terminal connected by a local control means to one of the power supply terminals. A control circuit receives on a first input a first full-wave rectified voltage representative of the supply voltage, and on a second input a second half-wave rectified voltage representative of the voltage applied to the local control terminal. To eliminate spurious orders, it compares a quantity G1 representative of at least one non-null sample of the second voltage to a percentage of a quantity G2 representative of associated samples of the first voltage, sampling of the two voltages being almost simultaneous. If G1≧0.8G2, the device considers that a control order has been received and if G1 ≦0.7G2, that no order has been received.

Abstract: A switching apparatus includes a pair of fixed coils and a pair of movable coils, with one pair being disposed between the other pair. Two of the coils may be connected back to back on opposite sides of a support plate to increase the stiffness of the coils and reduce damage due to impact between the fixed and movable coils. The coils include two sets of coils, each including one of the fixed coils and one of the movable coils. The coil sets can be driven simultaneously or at different times to perform contact opening and closing operation.

Abstract: A method of controlling a supply current applied to an electromagnet of an electromagnetic actuator by a control unit for obtaining a low impact speed of a reciprocating armature of the actuator upon arrival of the armature at a pole face of the electromagnet, includes the following steps: during travel of the armature toward the pole face detecting displacements of the armature and a sequence of the armature speed as actual values; comparing the actual values with a performance characteristic field stored in the control unit and relating to a predetermined relationship between armature speed and armature displacement for the armature travel toward the pole face; determining a desired value for the supply current from the comparison step; comparing an actual value for the supply current with the determined desired value; adjusting the supply current based on a difference between the actual and desired values; and applying the adjusted supply current to the electromagnet.

Abstract: In a control circuit for controlling a coil current flowing in an electromagnetic coil (21a) connected to a power source (73), a current processing circuit (72, 75, 76, 77) is connected to the power source to process the coil current into a pulse current with a duty ratio. For adjusting the duty ratio in response to variation of a voltage of the power source, a ratio adjusting circuit (79, 80, 81) is connected to the power source and the current processing circuit. The electromagnetic coil is included in a displacement control valve for varying a displacement of a variable displacement compressor.

Abstract: A fuel injector control circuit reduces the number of gates required by arranging high side and low side gates in a matrix. Each coil is selectively activated by activating a unique pair of a high side gate and a low side gate, thus reducing the total number of gates required.

Abstract: Lock for a vacuum chamber which lock has a passage comprising an outer sealing element and an inner sealing element which outer sealing element can be maintained in the closed position under the influence of the pressure difference caused by the vacuum in the vacuum chamber, and can be opened against the force caused by the pressure difference, which inner sealing element under pretension can be maintained in the opened position and comprises closing element for closing the inner sealing element against the pretension, the closing element comprise at least one electromagnet.

Abstract: A method for control of an injector in an internal combustion engine in which for a specific engine cycle, a control unit calculates a desired value of the opening time of the injector and forwards this desired value to a drive circuit of the injector, a supervision device calculates an actual value of the opening time of the injector during the injection phase, compares this actual value with the desired value and generates an error signal if the difference between the desired value and the actual value is outside a predetermined acceptability range.

Abstract: A method and device for driving an injector in an internal combustion engine in which a current wave which is variable over time, which comprises an initial section substantially of a pulse type and having a relatively high current intensity, an intermediate section during which the current intensity is rapidly reduced to substantially zero values and a final section having a substantially constant and relatively low current intensity, is caused to circulate through a control circuit of the injector.

Abstract: A method for starting up an electromagnetic actuator operating an engine cylinder valve. The actuator has two spaced electromagnets, between which an armature, connected to the cylinder valve, is reciprocated against a restoring spring from a center position to lie against a magnet pole face. An ECU alternatingly supplies the electromagnets with a capturing current, the level of which is regulated as a function of the approach of the armature toward a pole face, as detected by a sensor assembly. A reference temperature is detected for the magnets, and, at a normal temperature, the armature starts oscillating due to the alternating energization of the electromagnets, and is brought into contact with a pole face. Or, at a low temperature level, one of the electromagnets is supplied with a high current pulse.

Abstract: The device comprises two power supply terminals, a local control terminal and remote control and presence detection terminals. It can operate in fully autonomous manner, the power supply terminals being connected to a voltage supply source by means of a local control switch, closing of which causes excitation of a coil of the electro-magnet. It can also operate in conjunction with a communication module. In this case, the terminals are permanently supplied by the source, the local control terminal is connected to one of the power supply terminals by a local control switch and the remote control and presence detection terminals are connected to the module. The device automatically detects the presence of the module and causes excitation of the coil if the supply voltage is sufficient and if a control signal is applied to it either by the local control switch or by the module.

Abstract: A digital two-step controller for an actuator element includes an A/D converter, an output driver and a control device with a memory. An analog measuring signal is received from the actuator, converted in the A/D converter into an actual digital value, and is input into a first region of the memory of the control device. The actual digital value which is input into the first region of the memory is compared with a theoretical digital value for the actuator, which value is stored in a second region. The output of the control device to the output driver is set to ZERO when the actual digital value is larger or equal to the theoretical digital value. The output of the control device to the output driver is set to ONE when the theoretical digital value is greater than the actual digital value. After a sampling period &Dgr;t, another analog measuring signal is received from the actuator and the regulation steps are repeated in an interrupt called in cycles and corresponding to the sampling interval.

Abstract: The device comprises means for detecting an unscheduled movement of the movable core of an electromagnet during a holding phase. For this, a control and regulation circuit monitors the current flowing in at least one coil of the electromagnet. When, during a holding phase, the current flowing in the coil is greater than a setpoint value and either remains so during a preset time or is increasing, an unscheduled movement is then considered as being detected and the device makes the electro-magnet switch to inrush phase with a much higher current.

Abstract: In a port fuel injection lean burn engine, attaching of fuel spray onto a wall surface, which is a problem at atomizing injected fuel, is reduced, and the quality and shaping state of the mixed gas in cylinders of the engine is improved.

Abstract: In a power distribution system, synchronizing switchgear operations with an AC voltage or current waveform can be accomplished more precisely with a closed-loop feedback, microprocessor-based motion control design. By employing a closed-loop feedback, microprocessor-based design, switchgear contact position and velocity can be monitored and optimized in real time during a switching operation, thereby assuring a more accurate switching operation. Moreover, the closed-loop feedback design intrinsically compensates for the effects of such things as ambient temperature, AC waveform fluctuations, and changes in the physical condition of the switchgear. The closed-loop position feedback design is also capable of optimizing various transfer function parameters associated with the closed-loop feedback process, both during and subsequent to a switching operation, to further assure that switching operations are more accurately synchronized with the AC voltage or current waveforms.

Abstract: An outboard motor engine includes a plurality of cylinders. A fuel injector is disposed to inject a charge of fuel into an intake system. The fuel injector can form a portion of a direct injection system or a manifold injection system. The engine includes a processor that cycles each of the fuel injectors prior to energizing a fuel pump, a starter motor, or another electrical component of the outboard motor. By energizing the fuel injectors in sequence, a higher level of voltage can be applied to each fuel injector. In addition, by energizing the fuel injectors prior to energizing other electrical components, a higher level of voltage can be applied to each fuel injector.

Abstract: An electromagnetic operator includes first and second coils wound coaxially. An armature partially surrounds the coils for channeling flux during energization of the coils. The armature may be formed of a bent plate and secured to a ferromagnetic support. A control circuit applies energizing signals to the coils during operation. Both coils are energized during an initial phase of operation. One of the coils is subsequently released or de-energized automatically. A timing circuit removes current from the second coil after a variable time period. The time period may be a function of the configuration of the timing circuit, such as an RC time constant, and of the energizing signal.

Abstract: An electrical control module and circuit for controlling a solenoid. The control circuit provides a constant voltage to a solenoid for a predetermined time period after which a pulse width modulated voltage is supplied. The circuit further includes components for reverse polarity protection, transient voltage protection, low gate drive voltage protection, reduced heat dissipation and improved magnetic drive under low input voltage conditions during application of the pulse width modulated voltage. The module may be used in conjunction with a single coil or a dual coil solenoid. The circuit may be utilized on a 12 volt or a 24 volt electrical system without adjustment.

Abstract: A system for controlling the force and/or motion of an electromagnetic actuator. The actuator could be a solenoid, relay, or levitating device. The drive to the coil can be linear or switching, voltage or current and the sensors measuring the system can be as simple as just a current sensor monitoring the coil current or a flux sensor. Continuous control of position can be achieved allowing magnetic levitation or the soft landing of the moving element.

Abstract: An electromechanical relay drive system which prolongs relay life by ensuring operation of the relay in a manner to make and break contact between the contact electrodes at a zero crossing point of the switched waveform. Relay aging and environmental variations are dynamically compensated upon each actuation of the electromechanical relay to ensure proper timing of the energization and de-energization of the relay to ensure switching at the zero crossing point. Additionally, the drive system described compensates for variations in the actual contact operation during actuation for the positive and negative half cycle of the switched waveform. Furthermore, the system of the instant invention alternately energizes and de-energizes the electromechanical relay during the positive and negative half cycles of the switched waveform to prevent metal deposition from one contact electrode to the other.

Abstract: A control device includes a magnetic actuator, a final control element, a regulating unit and a measuring device. The magnetic actuator has a coil, a core, and an armature. The actuator is connected to the final control element. The measuring device determines an inductance value L of the coil and generates, as a function of the inductance value L, a first control signal by which a theoretical value of the amplitude of the current through the coil is changed to a holding value. When a pulse signal P is present, the current through the coil is regulated to the theoretical value by the regulating unit.

Abstract: The control device drives a power output stage, in particular of a fuel pump or a fuel injection valve. The control device has a series circuit with a highside switch, a first resistor and a first capacitor. A second capacitor is connected between a lowside switch and the highside switch. A further series circuit includes the first resistor, a second resistor and a second capacitor and is connected in parallel with the second capacitor. A further resistor is connected between the supply voltage terminal and the lowside switch.

Abstract: The present invention employs rotary switches that can be electromechanically set or reset remotely. Typical, although not limiting, is the use of the switch of the present invention by a trainer located remotely from students' STE. Manual operation is still possible. This allows the setting of the rotary switches to an initial position prior to the trainees beginning their testing. This facilitates remote setup and thereby saves the instructor significant time in manually resetting the rotary switches.

Abstract: A method and apparatus for power reduction in the operation of a power circuit for a relay or other electro-mechanical device having a first (higher) power requirement for the device to be activated, and a second (lower) power requirement for the device to be maintained includes charging a power supply capacitor to the necessary voltage for the first power requirement while the device is not activated, supplying current from the power supply capacitor to the device when it is activated until the voltage reaches the second power requirement, and keeping the power supply capacitor voltage at that second power requirement to maintain activation of the device.

Abstract: A exit bar for securing a door has a housing adapted for mounting to a door. A push pad for receiving a push force is mounted to the housing. A latch extends from the housing to releasably latch the door to which the exit bar is mounted. A link system links the push pad to the latch so that a push force exerted on the push pad releases the latch. An electromagnetic disposed in the housing causes an armature to engage the link system to retract the latch. The exit bar further dogs the latch in the unlatched position as long as the power control system for the electromagnet receives an operate signal and for a preestablished delay time after the operate signal has been removed.

Abstract: A solenoid operated remote resetting device with a protective solenoid activation circuit is disclosed. The device includes a housing for enclosing and protecting a solenoid with a movable plunger, a movable mechanical operator having an operator arm extending through an opening defined in the housing and a circuit board on which a solenoid activation circuit is mounted. The solenoid activation circuit includes circuitry for protecting the solenoid from overheating due to intentional or unintentional prolonged current flow in the solenoid.

Abstract: A solenoid driver circuit includes an input terminal for receiving a solenoid actuation pulse, an output terminal for connection to a terminal of a solenoid coil, a pull-in current adjustment terminal, and a hold-in current duty cycle adjustment terminal. A pull-in current duration circuit includes a first input coupled to the input terminal, an output producing a pull-in current duration pulse, and a second input coupled to the pull-in current adjustment terminal. A hold-in current duty cycle control circuit includes a first input coupled to receive a triangular waveform signal, a second input coupled to the hold-in current duty cycle adjustment terminal, and a third input coupled to the output of the pull-in current duration circuit. An output transistor includes a control electrode coupled to an output terminal of the hold-in current duty cycle control circuit, and a current carrying terminal coupled to the output terminal.

Abstract: A solid-state fail safe gas valve system in which first and second gas valves are arranged in series in a gas passageway, the valves being actuatable by first and second solenoid operators respectively, the second operator requiring a voltage greater than the operating voltage supplied to the valve system to achieve actuation. The operators are separately energized through microprocessor controlled switches so that a capacitor connected across the second operator and its switch is pumped to a voltage above the supplied voltage by voltage induced by interrupted energization of the first operator.

Abstract: A control valve of an engine fuel system includes a valve member which is coupled to an armature and is moved to engage a seating when a winding is energized. The current flow in the winding is first allowed to rise to a peak value to initiate movement of the armature and valve member at which time the winding is disconnected from the supply. The decay of current in the winding is controlled using two rates of current decay to ensure that the valve member moves into engagement with the seating with the minimum of bounce.

Abstract: An improved power management circuit for regulating current on a loop converts a high voltage, low current loop circuit to a low voltage source for devices associated with the loop. Additionally, the improved power manager provides a port for frequency shift key (FSK) transmit and receive signals.

Abstract: A method and a device for driving a load, particularly an electromagnetic load. The current flowing through the load is detected, and is controlled by a control device connected in series to the load. During a first phase, in addition to the control device, a first switching device is driven that is disposed parallel to the control device. During a third phase, in addition to the control device, a second switching device is driven that is disposed parallel to the control device.

Abstract: An electromagnet drive apparatus being characterized by a switching element 1 connected in series with a coil 3 of an electromagnet; a pulse signal generation circuit 16 which generates, on predetermined cycles, a pulse signal used for turning on the switching element; a regenerative circuit 4 which permits flow of a regenerated electrical current when the switch section is turned on and the switching element is turned off from a state in which the switch section and the switching element are in an on state and a source voltage is applied to the coil of the electromagnet, and which causes the power absorbing element to immediately reduce the regenerated electrical current flowing through the coil of the electromagnet when the switch section and the switching element are turned off; and a delay circuit 11 which turns on the switch section by application of the supply voltage and maintains the switch section in an on state until a predetermined period of time elapses after the application of the supply voltage

Abstract: A current control system for a linear solenoid for feedback-controlling an output voltage value on the basis of a difference between a command current value to the linear solenoid, as set according to a vehicle running state, and a feedback current value, as produced by monitoring a current value to be really fed to the linear solenoid, including: a decision circuit that decides whether or not the resistance value of the linear solenoid can be calculated; a real resistance value calculating circuit that calculates a real resistance value on the basis of a signal coming from the decision circuit, the command current value and the output voltage value; a comparison circuit that compares the calculated real resistance value and a resistance value in a memory unit; and a correction circuit that corrects the resistance value in the memory unit on the basis of the comparison result from the comparison circuit. The output voltage value is outputted on the basis of the corrected resistance value.

Abstract: A control system for an electronic device such as a solenoid for a vehicle transmission which is controlled by PWM. In the system, a difference (I.sub.H -I.sub.L) between the maximum value and the minimum value of current supplied to the solenoid is calculated and current supplied to the solenoid through a driver circuit is calculated based on the calculated difference and a predetermined coefficient as:I=I.sub.L +(I.sub.H -I.sub.L).times.Kduty.When a solenoid is controlled through PWM, feedback correction of the current flow becomes necessary owing to fluctuation in the voltage of the on-board power supply and fluctuation in the resistance of the electronic device with temperature. Since the instantaneous current in the solenoid varies constantly with the duty ratio, the detected value therefore differs depending on the sampling time point. Prior art smoothing solves the problem, but leads to raise the feedback high, causing overshooting.

Abstract: The magnetic residual energy stored in a coil is made to decay within a shorter and/or definite time period by the use of a free-wheeling circuit connected in parallel. The free-wheeling circuit comprises a series circuit, which includes a first diode and a first switching transistor connected in parallel to a non-linear resistor, connected in parallel to the coil. The first switching transistor is driven by a parallel circuit formed by a capacitor and a first ohmic resistor, which is connected in parallel to a second switching transistor. When a switch-off overvoltage appears in the coil, the second switching transistor becomes conductive and thus the first switching transistor is reliably blocked, so that the residual energy decays through the non-linear resistor.

Abstract: A proportional solenoid valve control system is applicable to hydraulic systems of heavy equipment, automatic transmission systems and furl injectors of vehicles. This system includes main circuitry which is composed of a switching element, a proportional solenoid valves, and a current detection resistor; and a control circuit which is composed of a current command detection circuit, a rectifier, an offset circuit, a current command adding and limiting circuit, an offset circuit, a current command adding and limiting circuit, a current detection circuit, an proportional integrator-controller, a pulse width modulation comparator, and an output circuit. In addition, the system, precisely controls the load currents flowing in the proportional solenoid valves according to the current commend.

Abstract: A magnet generator controller has a variable voltage array fabricated as a formation of receptacles mounted on a printed circuit board and interconnected via traces to pairs of taps off a transformer winding, and a plug-in connector that inserts in a selected receptacle to electrically couple one of various pairs of the taps to a field winding output in a mode of operation of the controller. This sets the voltage of the field winding output in the mode. The magnet generator controller also has a function select switch that allows selection of a run function in which the magnet generator controller sequences through plural modes (e.g., extra lift, lift, and drop modes) with associated field winding output settings in response to an operator control switch and timers. For use during set-up or fine-tuning, the function select switch also allows selection of exclusive mode functions in which the magnet generator controller operates indefinitely in an exclusive one of the modes.

Abstract: A solenoid valve driving device includes a bypassing current path of which one end is connected to a point between a first switching device and a first solenoid valve and another end is connected to a point between a second switching device and a second solenoid valve, and an element disposed in the bypassing current path and having a characteristic that causes current to flow from the first switching device side to a second switching device side. By adopting the above described constitution, through current generated when the first switching device is switched from an OFF-state to an ON-state during duty control of the first switching device can be suppressed by the inductance of the second solenoid valve. In this way, one solenoid valve among a pair of the first and second solenoid valves, which is not operated, has a function of suppressing the through current.

Abstract: A process and a device for controlling a movement of an armature of an electromagnetic switching element having an exciter coil. A first setpoint for the current can be defined after a first time. A second setpoint for the current can be defined after a second time. The second setpoint is smaller than the first setpoint. The second time also occurs before a third time at which the armature has reached its end position.

Abstract: A method and an apparatus for controlling an electromagnetic switching member having an excitation winding and a movable armature. A first time point and a second time point define a time window. Within the time window, the current characteristic and/or the voltage characteristic is evaluated in order to detect a switching time point at which the armature reaches a new limit position. The time window is enlarged if no reliable switching time point was detected within the time window.

Abstract: The control device has a drive circuit, in turn having a number of modular circuits--one for each inductor--activated selectively and receiving timing signals, and a common circuit connected to the modular circuits and cooperating with the activated modular circuit to supply the respective inductor. Each modular circuit has a first controlled switch connected between a first input terminal and a respective first output terminal, and a second controlled switch connected between the respective first output terminal and a storage capacitor; and the common circuit has a third controlled switch connected between the storage capacitor and a respective second output terminal, and cooperating with the second controlled switch to selectively transfer energy between the storage capacitor and the respective inductor.

Abstract: A non-burnout controller for a switching coil is disclosed. The controller has a pulse timer, a relay switch, and an actuation switch. After being reset and actuated, the pulse timer defines a pulse having a predetermined pulse period. The relay switch has a switch actuation input for receiving the pulse and first and second switch outputs for being electrically coupled to first and second taps of the switching coil. The relay switch places a switching voltage across the outputs during the pulse period such that the switching coil has a switching current running therethrough. The relay switch places a substantially zero voltage across the outputs before and after the pulse period such that the switching coil has substantially no switching current running therethrough. The actuation switch has first and second positions. Upon being changed to the first position, the actuation switch resets the timer, whereby the switching coil has substantially no current running therethrough.

Abstract: A device for deactivating a magnetomechanical electronic article surveillance marker includes first, second, third and fourth rectangular coils arranged in a two-by-two array in a common plane. Drive circuitry energizes the coils according to an operating cycle which includes three modes. In the first mode, all four coils are driven with respective alternating currents in phase with each other. In the second mode, the first and second coils are driven in phase with each other and the third and fourth coils are driven substantially in phase with each other and substantially 180.degree. out of phase with the first and second coils. In the third mode, the first and third coils are driven in phase with each other and the second and fourth coils are driven in phase with each other and 180.degree. out of phase with the first and third coils.

Abstract: A method and a device for driving an electromagnetic consumer (device) which includes a movable element, in particular a solenoid valve for metering fuel into an internal combustion engine. Within a timing window, a switching instant is determined by evaluating the time characteristic of a variable which corresponds to the current flowing through the electromagnetic consumer. A clocked voltage control is provided within the timing window.

Abstract: A microprocessor-based control for a solenoid operated device, wherein the microprocessor employs a tri-state output to achieve fast, precise control of the device without overburdening the microprocessor. The system has three selectable control modes: a first control mode in which the solenoid is de-energized, a second control mode in which the solenoid is fully energized, and a third control mode in which the solenoid is pulse-width-modulated. The various control modes are selected by the microprocessor and indicated by the logic level of a tri-state output. In the first and second control modes, indicated by first and second logic levels, the energization state of the solenoid is controlled directly by the microprocessor. In the third control mode, indicated by a third logic level, the energization state of the solenoid is controlled by an external PWM circuit based on PWM commands supplied to the PWM circuit by the microprocessor.

Abstract: An electric gun driver for controlling a solenoid within a dispenser which dispenses a liquid material, such as a heated adhesive, for application to packaging materials. The electric gun driver includes a switch mode power supply for receiving a wide range of input voltages so that the electric gun driver is adaptable to various power supply systems throughout the world. The improved electric gun driver also includes a computer for monitoring and regulating the operation of the dispenser device, a power circuit, and a hysteresis band modulator for receiving a reference current from the computer and a feedback current from an operational amplifier so as to provide a modulation signal to the power circuit. The power circuit includes two switches in the form of insulated gate bipolar transistors respectively controlled by gate driver and detector circuits so as to modulate the solenoid current for controlling and regulating the dispenser.