Abstract: A battery polarity determination circuit includes a battery accommodating unit including a first contact and a second contact to be in contact with respective electrode terminals of a battery, a control device that is connected via a resistor to a voltage lead-out point at which a voltage of the battery is led out and determines a polarity of the battery, a connection switching circuit capable of switching between a first connection state and a second connection state, and a diode having a cathode to be connected to a voltage read-in point at which the resistor and the control device are connected to each other, and an anode to be grounded, wherein the control device determines the polarity of the battery based on a voltage at the voltage read-in point according to the connection state of the connection switching circuit, and a forward voltage of the diode is set so that the voltage at the voltage read-in point is not less than a lower limit value of an absolute maximum rating of the control device.

Abstract: In an aspect a connector for charging an electric vehicle. A connector includes a coupling mechanism. A coupling mechanism is configured to mate with an electric vehicle port of an electric vehicle. A coupling mechanism includes a fastener for removable attachment with an electric vehicle port. A connector includes at least a direct current conductor. At least a direct current conductor is configured to supply a direct current to an electric vehicle. A connector includes a power supply circuit. A power supply circuit is configured to regulate a direct current supplied to an electric vehicle as a function of a power threshold.

Abstract: The present invention relates to mobile electronic device enclosures, and in particular to enclosure systems for docking and charging operations. The system comprises a mounting head, and a back housing of a mobile electronic device enclosure. The back housing of a mobile electronic device enclosure is removably attachable to the mounting head. The back housing comprises a charger control unit comprising a first power connection port, and a second two-way power connection port.

Abstract: A vehicle includes a charging stop switch that accepts a stopping operation for stopping external charging, and an ECU that stops the external charging when the stopping operation is accepted at the charging stop switch. The ECU determines whether or not a specific operation different from the stopping operation at the charging stop switch has been accepted, and when it is determined that the specific operation has been accepted, disables acceptance of the stopping operation. The specific operation is an operation different from an intended operation of a prescribed subject. The vehicle includes an inlet to which a charging connector for external charging can be connected. The ECU detects connection of the charging connector to the inlet, the prescribed subject is the charging connector, and the specific operation is a prescribed number of operations of connecting and disconnecting the prescribed subject within a prescribed time period.

Abstract: A jumper cable device, comprising an input port, two clamps, a main controller, a clamp polarity detection module and a clamp connection module. The input port is configured to be connected to a startup power source. The clamps are configured to be connected to a battery of a load. The clamp polarity detection module and the clamp connection module are connected to the main controller and the clamps. When the clamps are connected to the battery, the clamp polarity detection module detects polarities of electrodes of the battery to which the two clamps are connected, and the main controller acquires a detection result signal therefrom, control the clamp connection module according to the detection result signal to determine polarities of the two clamps according to the polarities of the electrodes of the battery and connect circuits between the input port and the two clamps to boost the battery.

Abstract: When a prescribed operation is performed during execution of AC charging, an ECU of a vehicle performs a charging stop process. The ECU determines whether or not a resume condition is satisfied during the charging stop process. When the resume condition is satisfied and when a charging connector is connected to an inlet, the ECU brings a locking device to a locked state and resumes the AC charging. When the resume condition is not satisfied or when the charging connector is not connected to the inlet, the ECU does not resume the AC charging.

Abstract: A vehicle includes: an inlet configured to allow a connector of a charging cable to be inserted into the inlet; a battery configured to be charged from a charger through the connector and the inlet; a communication device configured to perform communication with a server; and an ECU configured to control charging. The ECU diagnoses whether there is an abnormality in the charger, when where the charger and the vehicle are connected to each other through the charging cable, the abnormality being able to be diagnosed in a state where the connector has been inserted into the inlet, and sends information indicating an abnormality occurrence, to the server through the communication device, when where the ECU diagnoses the charger as having the abnormality.

Abstract: In a reverse connection protection circuit, a protection element enters a conductive state when the power source is electrically connected in a forward direction to a load-side circuit and enters a non-conductive state when the power source is electrically connected in a reverse direction to the load-side circuit. The protection element has a first terminal electrically connected to a power source-side terminal of, and a second terminal electrically connected to a load-side terminal of the switching element. A booster circuit is electrically connected to the load-side terminal to supply a boosted voltage of more than a power source voltage to the load-side terminal. A voltage detection part is connected to the load-side terminal to detect an output voltage of the switching element. A judgment part is connected to the voltage detection part to detect a switching element failure based of the voltage detected by the voltage detection part.

Abstract: Disclosed is a photovoltaic module. The photovoltaic module includes a solar cell module including a plurality of solar cells, and an inverter unit to receive a direct current (DC) voltage from the solar cell module and convert the DC voltage received from the solar cell module into an alternating current (AC) voltage without converting a level of the DC voltage received from the solar cell module.

Abstract: The present disclosure provides a signal loading method and a signal generator. The signal loading method includes: loading a first pair of voltage signals to at least one pair of separate signal channels for a time period, respectively, wherein the first pair of voltage signals have a first voltage difference therebetween; and determining whether a short circuit occurs in the at least one pair of signal channels within the time period, and if it is determined that no short circuit occurs in the at least one pair of signal channels within the time period, loading a second pair of voltage signals having a second voltage difference therebetween to the at least one pair of signal channels at the end of the time period. The second voltage difference is greater than the first voltage difference.

Abstract: A light emitting diode (LED) emergency light with transportation mode includes an alternating current (AC)-direct current (DC) LED driving circuit, a light source, and an emergency module, wherein the emergency module includes a battery, the AC-DC LED driving circuit is electrically connected to a terminal of the light source, and the emergency module is electrically connected to another terminal of the light source. After the emergency module generates a transportation mode signal, the LED emergency light enters the transportation mode, and a power supply circuit within the emergency module utilizing the battery to drive the light source is turned off according to the transportation mode signal. Therefore, after the LED emergency light enters the transportation mode, current consumption of the LED emergency light is decreased significantly, so the present invention greatly extends storage time of the LED emergency light during a transportation and warehouse process of the LED emergency light.

Abstract: An apparatus configured to protect one or more system components from damage due to reverse polarity connection of a power supply comprising a relay located between said power supply and said components, and configured to detect when a power supply is provided with reverse polarity and to consequently switch the relay to an open state to isolate said power supply from said components.

Abstract: The present invention provides a battery clamp, comprising: a first and second wire clamps and a control device. Each of the first and second wire clamps is electrically connected to the control device. The control device comprises: a housing; a master-control board mounted within the housing; and connectors disposed at one side of the housing, and being electrically connected to the master-control board, comprising: at least a first and second electrode connectors, which are connected to an external power supply for receiving power, and at least one communication connector connected to the external power supply for building a communication connection between the battery clamp and the external power supply. The battery clamp is communicatively connected to the external power supply by the communication connector, thereby effectively solving the problems of a lithium battery in an external power supply e.g. battery bulge or explosion resulted from improper uses.

Abstract: With a relay control device according to an embodiment, a regenerative current from a relay coil which is disposed in a relay flows through a coil energy absorption circuit, which is connected to the low side of the relay coil, toward the ground. A current detection resistor, which is a shunt resistor, is connected further toward the ground side of the coil energy absorption circuit than a coil surge absorption resistor, and the potential of the current detection resistor is compared to a reference potential, with a current detection circuit. Furthermore, on the basis of the result of the comparison with the current detection circuit, an off-duty period of the PWM control is terminated before the current which flows through the relay coil becomes less than or equal to a minimum drive current.

Abstract: The invention relates to an electrical plug (24) having a connection unit (36) which can be coupled to an electrical line (26) in order to transmit electrical energy, having at least one electrical contact pin (30) which has a plug section (32) and a coupling section (34), wherein the coupling section (34) is electrically coupled to the connection unit (36), and wherein the plug section (32) is designed to provide a releasable plug connection to an associated contact socket (18) in order to electrically couple the contact pin (30) to the contact socket (18), and having a detection unit (38) which is designed to) detect a tensile force which is exerted on the contact pin (30) and/or a movement of the contact pin (30) relative to the contact socket (18), and to provide a disconnection signal for interrupting the energy transmission process.

Abstract: A system and method for a double source battery charger of an engine-generator. The double source battery charger of the engine-generator includes an electric starter and a battery. The electric starter is selectively energized by the battery to start an engine of the engine-generator. The double source charger maintains the battery at a desired charge such that the battery has sufficient charge to energize the electric starter. The double source battery charger is selectively coupled to one of two power sources to charge the battery: an alternator of the engine-generator and an external AC source, such as a standard 120 Volt or 240 Volt wall outlet. As a result, the battery is charged by either power from a wall outlet or, if the generator is running, by power provided from the alternator.

Abstract: A charging system for a mobile device includes a transmitter and a receiver. The transmitter includes (a) a first interface to a power source; (b) a second interface to the receiver; (c) a polarity detection circuit for detecting polarities of the; and (d) first and second switches controlled by the polarity detection circuit, wherein each switch selectively connects a terminal of the first interface to a terminal of the second interface. The receiver includes: (a) a first interface; (b) a second interface coupled to a device to be charged; and (c) a connection circuit between a terminal of the first interface and a terminal of the second interface, wherein the connection circuit is conductive when the voltage across these terminals is of a first polarity, and a second polarity otherwise.

Abstract: A power conduit for charging a power storage device of a vehicle includes an output terminal and locking mechanism operatively disposable in one of an engaged and a disengaged position. The locking mechanism locks the output terminal to the vehicle when the locking mechanism is in the engaged position and unlocks the output terminal when in the disengaged position. The power conduit includes a controller including a memory device configured to store a plurality of computer-executable instructions and a processor coupled to the memory device. The instructions configure the processor to receive an identifier associated with one of the vehicle and a user of the vehicle, and generate and transmit an unlocking signal to cause the locking mechanism to be in the disengaged position upon one of a determination that the identifier was received and a determination that a predetermined charge state of the power storage device has been reached.

Abstract: An alternating current (AC) induction machine, such as a medium voltage induction motor, includes an auxiliary electrical connection box that is incorporated in the terminal box or within separate auxiliary electrical connection boxes that, are coupled to the machine's incoming power source. The box includes power conversion transformers or bridges that respectively convert the incoming AC power to other AC voltages or direct current (DC) useful for operating auxiliary devices proximal the machine. The connection box avoids the need to run separate power lines to induction machines necessary for operating auxiliary devices. Exemplary auxiliary devices include external auxiliary AC powered cooling fans for medium voltage AC motors. The auxiliary connection box may reconfigurable in the field and/or be pre-configured to provide one or more common auxiliary device output power sources.

Abstract: Disclosed is a charging cradle for a headset device, which includes a housing with a surface providing a mounting depression, and a cover with a transparent surface pivotably connected to the housing so as to open and close the mounting depression. The headset device is mounted in the mounting depression so as to charge an internal battery pack provided in the headset device. The cradle protects the headset device under charging, enabling the user to observe the charging state without opening it. An earphone cover for a headset device includes a projected semi-circular fixing ring for preventing the earphone from being removed from the ear. The earphone cover is provided in various sizes to fit a user's ear size, and may be rotated to change the rotational position of the fixing ring so as to enable the user to put the headset device selectively on the right or left ear.

Abstract: The invention discloses a charging circuit and a method for preventing charging power supply from reversely connecting in an electronic cigarette or electronic cigarette case. The charging circuit comprises a direct current input terminal, an unit for preventing charging power supply from reversely connecting, a charge management unit and a rechargeable battery. The unit is electrically connected to the direct current input terminal; the charge management unit is electrically connected to the unit and the rechargeable battery. The charging circuit and method according to these embodiments of the invention can effectively avoid the risk caused by the reverse connection of the charging power supply for the electronic cigarette or the electronic cigarette case; it also has the advantages such as low voltage drop and low power consumption.

Abstract: A vehicle is provided with a connection signal line having electric potential is changed when a connector of a power charging cable is attached to a control pilot line through which a pilot signal CPLT is transmitted from the power charging cable. The charging connector is attached to a vehicle in place of the power charging cable. The power supply connector includes a first connection portion connected to the connection signal line and a second connection portion connected to the first connection portion and the control pilot line.

Abstract: There are provided a control device, a power-supply cord, and a charging cable to be connected to an automobile, wherein the control device includes an electric-leakage detection portion for detecting an electric leakage in the charging cable or the automobile, a connection detection portion for detecting the charging cable being connected to the automobile, and a power-supply interruption portion for controlling supply of electricity from the power-supply cord to the charging cable, and, further, the control device has a function of activating the electric-leakage detection portion in a predetermined case, in a state where the automobile charging apparatus is supplied with a commercial power supply.

Abstract: A system for protecting a power consuming circuit, the system comprising two terminals for receiving power and two terminals for providing received power. Between one of the receiving terminals and a providing terminal, a transistor is provided which is controlled by a Zener diode and to break the connection between one of the receiving terminals and a providing terminal, if a voltage over the providing terminals or the receiving terminals exceeds the breakdown voltage of the Zener diode.

Abstract: A battery fuel gauge apparatus comprises a current amplifier formed by a first transistor and a second transistor. Both transistors operate in the same operation conditions except that the second transistor has a smaller channel width in comparison with that of the first transistor. The first transistor is connected in series with a battery pack. The second transistor is connected in series with a sensing device. The sensing device comprises a first resistor and a second resistor connected in series. The first resistor has a positive temperature coefficient and the second resistor has a negative temperature coefficient.

Abstract: Aspects relate generally to hot swap control in uninterruptible power supply units for systems requiring backup power. A unit may include a pair of MOSFET switches configured as a bidirectional switch for battery charging and discharging current control. This configuration allows the unit to limit inrush current when the unit is connected to a DC power bus of a power system and also allows the unit to eliminate any current flow when it is disconnected. Upon insertion and extraction of the unit, the MOSFET switches are disabled to prevent any disturbances on the DC power bus. Hot swapping in the unit ensures that the overall power system, including the unit and the DC bus, operates reliably.

Abstract: A handheld device for jump starting a vehicle engine includes a rechargeable lithium ion battery pack and a microcontroller. The lithium ion battery is coupled to a power output port of the device through a FET smart switch actuated by the microcontroller. A vehicle battery isolation sensor connected in circuit with positive and negative polarity outputs detects the presence of a vehicle battery connected between the positive and negative polarity outputs. A reverse polarity sensor connected in circuit with the positive and negative polarity outputs detects the polarity of a vehicle battery connected between the positive and negative polarity outputs, such that the microcontroller will enable power to be delivered from the lithium ion power pack to the output port only when a good battery is connected to the output port and only when the battery is connected with proper polarity of positive and negative terminals.

Abstract: A charging circuit includes a power path control unit which switches a first switch connected between a system connection terminal and a battery connection terminal on while not charging, and switches the first switch on and a second switch connected between an external power supply input terminal and the system connection terminal on while charging so as to supply power to a system and charge a battery. A voltage difference between the external power supply input terminal and the battery connection terminal is detected, a current flowing between the external power supply input terminal and the system connection terminal is detected, and it is determined that an external power supply is disconnected based on the detection results of the voltage differences and the current.

Abstract: Disclosed herein is a charging apparatus using a pad type electrode contact point, the charging apparatus including: a charging plate having a plate shape; and an attaching plate installed on a portable terminal to provide the power to a charging circuit of the portable terminal.

Abstract: Methods, electronic devices and USB charger apparatus are presented for fast USB charging, in which a high voltage master of the device detects a connected high voltage charger and selectively connects a current circuit to source or sink a current to or from one USB cable data signal conductor while providing a non-zero voltage to the other USB cable data signal conductor to configure the charger apparatus to provide charging power at a particular high voltage level above a nominal voltage level.

Abstract: A charger that evaluates the effectiveness of the charging field generated by the charger at an implantable device. The charger includes a charging coil, a communication module, and a processor. The processor can include instructions to determine the effectiveness of the charging field based on one or several signals or communications received from the implantable device. The charger can use the determination of the effectiveness of the charging field to vary the strength of the charging field and/or to prompt the user to move the charger with respect to the implantable device.

Abstract: A load management system provides an interface between a power input and several switched power outputs and un-switched power outputs. A controller groups the switched power outputs into one or more load groups based on a switched current limit determined for the system and the measured currents of the electrical loads. The load groups are defined so that the sum of electrical load currents in each load group does not exceed the switched current limit. The controller also activates one or more switches to apply electrical power to the load groups according to a power sequence. A method for distributing electrical power to electrical loads using load groups is also provided.

Abstract: This disclosure relates to method and apparatus for selecting right and left configurations of hearing assistance device circuits, such as battery polarity. In various applications the present subject matter is applicable to a flexible circuit in hearing assistance devices, including but not limited to hearing aids. In one example, a printed circuit board is configured during manufacture to be used in either a left or a right hearing assistance device. The printed circuit board includes a solder selectable portion to provide for selection of left or right during assembly of the hearing assistance device, according to various embodiments.

Abstract: Stated is a charging-current regulating device for charging an energy storage device for a field device, and for regulating a charging current for the energy storage device, wherein regulating the charging current for the energy storage device takes place in such a manner that a limiting value relating to an input current of the field device is not exceeded. Regulating the charging current may take place in such a manner that energy storage takes place as quickly as possible and without overloading an input protection circuit of the field device.

Abstract: A control circuit is provided which includes a pre-charge circuit connected in parallel with a solid state switching device of, for example, a power distribution network. The pre-charge circuit pre-charges a load capacitance at a load side of the switching device prior to activation of the switching device. The pre-charge circuit includes a threshold waveform generation circuit and an over-current detect circuit. The threshold waveform generation circuit synthesizes a maximum acceptable charging waveform for the pre-charge circuit in charging the load capacitance, and the over-current detect circuit signals an over-current fault condition upon a charging current through the pre-charge circuit exceeding the synthesized, maximum acceptable charging waveform. The pre-charge circuit includes a sense resistor coupled to a power input side of the solid state switching device, with charging current through the pre-charge circuit being monitored via the sense resistor.

Abstract: Systems and methods for implementing a safety circuit in charging devices are disclosed. In an exemplary embodiment, a method may include closing a latch to stop delivery of a charging current to a battery when voltage produced by the battery indicates that the battery is non-rechargeable. The method may also include dropping a threshold from an initial value for the voltage produced by the battery to a baseline value so that the latch remains closed even if the voltage produced by the non-rechargeable battery drops below the initial value of the threshold. The method may also include resetting the latch each time a battery is connected to the charging device.

Abstract: Improved protection for a rechargeable battery from damage by being discharged below a cut-off voltage is provided. The measured voltage of a battery under load is lower than the measured voltage of the battery under no load. As the cut-off voltage for the battery is specified as a no load voltage, comparing the measured voltage of the battery under load to the cut-off voltage would result in stopping use of the battery with useable charge remaining. Through testing, a set of relationships for estimating the no load voltage of a battery under load has been determined. Using this set of relationships with battery measurements, an estimated no load voltage for the battery is determined. This estimated no load voltage is compared to the cut-off voltage. This allows for full use of the battery while stopping use of the battery when its voltage reaches the cut-off, thereby preventing damage.

Abstract: Described herein are techniques related to near field coupling and wireless charging or wireless power transfer (WPT). More particularly, an induced current at a receiving coil antenna is measured and utilized as a basis for re-alignment with a transmitting coil antenna is described.

Abstract: A battery alarm for use with a battery assembly is provided, the battery alarm including a first activation component, a signaling component, and an output component. The first activation component is configured to activate the alarm upon disengagement of the battery assembly from a battery-operated device and is further configured to deactivate the alarm upon engagement of the battery pack with the battery-operated device. The signaling component is coupled to the first activation component and is configured to transmit a signal when the alarm is activated. The output component is adapted to receive the signal from the signaling component and is configured to produce a visual, audible, and/or tactile output upon receipt of the signal from the signaling component.

Abstract: A battery load detecting device includes: a battery check pulse generator generating a check pulse in response to a check enable signal; a constant voltage regulator generating a battery status signal in response to a first battery check signal; and a battery detection determining unit comparing a predetermined reference signal with the battery status signal to generate a comparison result signal, using the comparison result signal and the check pulse to generate a second battery check signal, and using the second battery check signal to generate a battery detection signal indicating whether a chargeable battery is electrically connected to the constant voltage regulator.

Abstract: An object of the invention is to provide a battery control apparatus capable of accurately obtaining permissible charging or discharging power in keeping with variation of the internal resistance of a battery. The battery control apparatus of this invention includes an internal resistance table in which the internal resistance value of single cells corresponding to the temperature and state of charge thereof are described in association with each of charging or discharging duration time of the single cells. The battery control apparatus calculates a permissible charging current or a permissible discharging current by using the internal resistance value described in the internal resistance table and controls the charging or discharging of the single cells in accordance with the current value thus obtained.

Abstract: A system, method, and computer program product are provided for remedying a charging error. In use, a battery and a battery charger are identified. Additionally, an error associated with the charging of the battery by the battery charger is detected. Further, the error is remedied.

Abstract: An input power circuit for a battery-powered device, such as a toy or consumer electronic device, includes a polarity correction circuit portion. The device includes a first input terminal and a second input terminal, a first output terminal and a second output terminal, and a diode with a forward voltage drop of about 0.5 volts or less. In embodiments, the polarity correction circuit portion is configured to provide a positive voltage polarity at the first output terminal and a negative voltage polarity at the second output terminal for any polarity of power at the first input terminal and the second input terminal. The polarity correction circuit portion can include a diode bridge, and the diode may include a Schottky diode or a germanium diode.

Abstract: An integrated charger and alarm unit. A plurality of alarm receptacles are in a housing, each for selectively receiving a sensor cord for sensing security status of one of a plurality of chargeable devices. A plurality of charging receptacles are in the housing, one for each alarm receptacle, each for selectively receiving a power cord for charging one of the chargeable devices. A power receptacle in the housing connects to an electrical power source. An electrical circuit is operatively connected to the alarm receptacles, the charging receptacles and the power receptacle. The electrical circuit comprises an alarm control powered by the electrical power source and connected to the alarm receptacles and generating an alarm signal if the security status of any of the plurality of chargeable devices is in an unsecured status. A power supply control regulates power from the electrical power source to each of the charging receptacles.

Abstract: An assembled battery monitoring device that detects presence of disconnection in wiring pulled from an assembled battery in which a plurality of electric cells are connected in series. The electric cells are connected respectively in parallel to auxiliary current channels each having a setting resistance value, and the presence of the disconnection in the wiring is detected based on a detection voltage when the switching device for auxiliary current channel is turned to the closed state.

Abstract: A startup self-diagnostic apparatus for an electrical storage system including an electrical storage device, a charge and discharge switch device disposed to be connected to the electrical storage device, an electrical storage device breaker disposed between the electrical storage device and the charge and discharge switch device, and a load side breaker disposed between the charge and discharge switch device and an external load comprises a state monitoring unit for the electrical storage device breaker, a state monitoring unit for the load side breaker, a converter diagnosing unit, a switching device diagnosing unit, and an electrical storage device monitoring unit, for diagnosing peripheral diagnostic items which may be diagnosed without using the electrical storage device.

Abstract: A circuit arrangement that has an energy source that can provide a charging voltage for charging an electrical energy storage unit in a charging circuit when it is connected to an energy supply, wherein it is possible to represent the charging voltage using an alternating quantity, and that has a capacitor circuit having a first capacitor element, a first valve element, and the energy source, wherein the first capacitor element is charged by the energy source via the first valve element if the charging voltage is negative, so that, if the charging voltage is positive, the voltage over the first capacitor element has the same orientation in the capacitor circuit, in terms of sign, as the charging voltage, and the voltage over the capacitor element.

Abstract: An alarm system associated with a charge cord of a plug-in vehicle is provided. The system includes a sensor configured to evaluate a status of the charge cord, including a coupled status when the charge cord is coupled to the vehicle and a decoupled status when the charge cord is not coupled to the vehicle. The system further includes an alarm interface coupled to the sensor and configured to activate an alarm when the charge cord is in the decoupled status.

Abstract: A storage battery system includes a battery module including nonaqueous electrolyte secondary batteries. The storage battery system further includes a temperature sensor which measures a temperature of the battery module, a voltmeter which measures a voltage of each of the nonaqueous electrolyte secondary batteries and a charge control unit which controls a maximum end-of-charge voltage V1 (V) of the nonaqueous electrolyte secondary batteries to fall within the range defined in formula (1) given below when the temperature of the battery module is not lower than 45° C. and is not higher than 90° C.: 0.85×V0?V1?0.

Abstract: A current sensor includes a magnetic balance sensor and a switching circuit. The magnetic balance sensor includes a feedback coil which is disposed near a magnetic sensor element varying in characteristics due to application of an induction field caused by measurement current and which produces a canceling magnetic field canceling the induction field. The switching circuit switches between magnetic proportional detection and magnetic balance detection. The magnetic proportional detection is configured to output a voltage difference as a sensor output. The magnetic balance detection is configured to output, as a sensor output, a value corresponding to current flowing through the feedback coil when a balanced state in which the induction field and the canceling magnetic field cancel each other out is reached after the feedback coil is energized by the voltage difference.