Abstract: A DC to three-phase AC inverter system includes a three-phase motor, an inverter circuit, switching elements, a capacitor, a DC power source and a control circuit. The DC power source is connected to the three-phase motor at a neutral point thereof. The control circuit calculates voltage commands, first through third divided boost commands by dividing a boost command, and first through third drive signals based on the voltage commands and the first through third divided boost commands. The second and third divided boost commands are used when the PWM control is performed by turning on and off the switching elements for the second and third phases while the switching elements for the first phase continues to be on or off state is set larger than those used when the PWM control is performed by turning on and off the switching elements for the first through third phases.

Abstract: Disclosed is an apparatus for adaptive illumination charging, including: an image process sensor for detecting an external image information; a pixel sensor unit for receiving light of the image information detected by the image process sensor, the pixel sensor unit including multiple pixels; a light quantity calculator for calculating average quantity values of light received by pixels of the pixel sensor unit within a specific area during a pre-set time period; a controller for searching for a location of a pixel corresponding to an average value with a highest light quantity average among the average quantity values of the light and notifying of the search result; and a solar battery for generating energy according to a quantity of light received by the pixel sensor unit.

Abstract: A portable terminal includes a cover movably coupled to a body, a first solar cell on the body; and a second solar cell on the cover. The first and second solar cells may be oriented in the same or different directions. When oriented in the same direction, both solar cells may receive light when the cover is opened relative to the body. The solar cells output voltages for simultaneously charging a battery when the cover is opened and when voltages from the first and second solar cells exceed a predetermined reference voltage.

Abstract: A battery module for use with a vehicle electrical system. The battery module includes a bi-directional battery voltage converter, a first battery, and a second battery. A first relay selectively connects the first battery to the bi-directional battery voltage converter. A second relay selectively connecting the second battery to the bi-directional battery voltage converter. A controller selectively energizes the first relay, selectively energizes the second relay, and controls a direction of current through the bi-directional battery voltage converter.

Abstract: A system for recharging a plug-in hybrid vehicle and a control method are provided to recharge a battery with exterior AC electricity plugged in. The system includes a motor operated as an electric motor or a generator, a battery in which DC voltage is stored, an inverter disposed between the motor and the battery, a plugged in exterior AC electric power source supplying electrical energy, a single phase inductor disposed between the inverter and the AC electric power source, a switch which electrically connects or disconnects the motor, a current sensor that detects current value supplying to the motor, and a controller which controls the switch to disconnect electric connection between the inductor and the motor and controls the inverter not to supply current to the phase which is not connected to the inductor when the AC electric power source is plugged in.

Abstract: An energy-efficient and compact battery charger. The battery charger includes, among other things, a charging port, a power supply module, a battery charger control module or controller, a power control safety module, a battery charger switch, and an indicator. The controller, the power control safety module, and the battery charger switch work in conjunction with each other to control the operation of the battery charger. The controller is configured to execute a charging control process which detects the insertion of a battery pack into the charging port, controls the charging of the battery pack, and controls the illumination or display of the indicator. The power control safety module includes a power control safety circuit that is configured to prevent the charging current and/or the charging voltage from damaging the battery charger or battery pack during a malfunction.

Abstract: A novel switching hysteretic bidirectional power converter is presented. The converter includes the generation of a synthetic ripple signal and feedback networks to hysteretically control the power converter both when the converter operates as a boost converter with the flow of power in one direction, and when the converter operates as a buck power converter with the flow of power in the opposite direction. The presented approach provides a switching converter with a much simpler control method with respect to conventional inductive bidirectional power converters. The hysteretic control provides stable operation in all conditions with excellent load and line transient response. Furthermore this allows the operation of the bidirectional power converter with much higher switching frequencies with respect to state of the art conventional approaches, thus reducing the cost and size of the passive components storing energy during the conversion.

Abstract: The electronic apparatus allows a user to arbitrarily set a display of a remaining battery level. The apparatus includes a detector which detects a remaining battery level of a battery, and a threshold-value-setting part which is operated by a user to set a threshold value for performing a display relating to the remaining battery level. The apparatus further includes a controller which displays in a display device an image representing the remaining battery level in accordance with the result of a comparison between the remaining battery level detected by the detector and the threshold value set with the threshold-value-setting part.

Abstract: An automated power reporting system is provided in one aspect. The system includes one or more devices that can report or transmit power status information over a bus or network. A protocol component utilizes a generalized protocol to process or convert the power status information over the network in order to facilitate power management operations for a plurality of devices. In this manner, devices that send power information can interact and exploit personal computing resources in order to better help users manage limited power resources for their respective devices.

Abstract: A detecting module is for detecting a battery equalizer of a power supply device. The detecting module includes a current detecting unit, a drive circuit, and a control circuit. The current detecting unit is to be coupled to the battery equalizer and a battery set of the power supply device, and generates an output based on detected current flow through the battery equalizer. The drive circuit is to be coupled to the battery equalizer for driving operation of the battery equalizer. The control circuit is coupled to the drive circuit and the current detecting unit, controls the drive circuit to drive operation of the battery equalizer and determines, according to the output of the current detecting circuit, whether the battery equalizer is in a normal operating state.

Abstract: A digital controlled battery charger comprises a power converter, a voltage sensor, a current senor, a mode selector and a digital controller. The voltage sensor and current sensor detect the voltage of a rechargeable battery and the current flowing through the rechargeable battery respectively. The mode selector selects a feedback signal from either the output of the voltage sensor or the output of the current sensor. The digital controller receives the selected feedback signal and generates a pulse width modulated signal for the power converter. Additionally, the digital controller is capable of dynamically adjusting its coefficients so that the control loop can maintain a stable system when the battery charger operates in different battery charging phases.

Abstract: There is provided a method for operating a lead acid storage battery in order to compensate for fluctuations in the amount of power generated by a solar power generation apparatus, a wind power generation apparatus, or another natural energy power generation device, the lead acid storage battery being charged by a power generation device and discharged to a load. The state of charge of the lead acid storage battery is maintained in a range of 30 to 90% where the fully charged state of the lead acid storage battery is 100%; and the lead acid storage battery is charged and discharged while the battery voltage is kept in a specified range of 1.80 to 2.42 V per cell to extend the service life of the battery. A reference temperature of 25° C. is established, and when the ambient temperature has risen above or fallen below the reference temperature, the upper and lower limit values of a specified range are corrected within a range of ?4 mV/° C. to ?6 mV/° C.

Abstract: Consistent with an example embodiment, a circuit comprises a power factor correction stage having a DC input, a ground input, a DC output and a ground output. The circuit further includes a capacitor; a diode; and a discharge circuit. A first terminal of the diode is connected to an input of the power factor correction stage, a second terminal of the diode is connected to the first plate of the capacitor; and the second plate of the capacitor is connected to the other input of the PFC stage. The discharge circuit is connected to the capacitor and is configured to discharge the capacitor such that it contributes to the output of the PFC stage when the level of a signal at the input of the PFC stage falls below a threshold value.

Abstract: A zero current detecting circuit is disclosed. The zero current detecting circuit includes a first zero current comparator for determining current variation on an inductor of a synchronous switching power converter so as to accordingly turn off a down-bridge transistor of the synchronous power converter; a second zero current comparator for determining whether the first zero current comparator turns off the down-bridge transistor too early or too late and outputting a comparison result, and a counter coupled to the second zero current comparator for ascending or descending a control bit according to the comparison result.

Abstract: A comparator type power supply controller that controls an output voltage. The power supply controller includes a comparator that compares a feedback voltage, which corresponds to the output voltage, with a reference voltage, wherein the comparator instructs power supply when the feedback voltage decreases when the feedback voltage decreases from the reference voltage. An offset application circuit is coupled to the comparator. The offset application circuit controls an input offset voltage of the comparator and decreases the input offset voltage as time elapses when the feedback voltage becomes lower than the reference voltage after the power supply ends. An amplifier amplifies a voltage difference of the feedback voltage and the reference voltage. The offset application circuit increases a change speed of the input offset voltage as the voltage difference increases in accordance with an output voltage of the amplifier.

Abstract: The present invention relates to a protection circuit for protecting a half-bridge circuit. The protection circuit detects an incorrect response of the half-bridge by monitoring the current of a first switch at a series resistor of a second switch. The protection circuit has a detector for detecting the voltage across the resistor and an evaluation circuit which is designed in such a manner that it evaluates an output signal from the detector after the first switch has been switched on and provides a fault signal at an output when the voltage across the resistor is greater than the threshold voltage.

Abstract: Methods and systems to generate a digital error indication of an input signal relative to a reference signal, using resistors, comparators, and latches. The digital error indication may indicate that the input signal is within a range of the reference signal, above the range, or below the range. The methods and systems may be implemented within a multi-phase digital voltage regulator to generate a digital error indication for each of a plurality of phase currents relative to an instantaneous average of the phase currents. The digital voltage regulator may be fabricated on an integrated circuit die with a corresponding load, such as a processor. The digital voltage regulator may include a plurality of multiplier or look-up based gain modules, each to receive a corresponding one of the digital error signals and to output one of three values. Outputs of each gain module may be integrated over time.

Abstract: A fully integrated DC-DC converter utilizes digitally controlled dual output stages to achieve fast load transient recovery is presented. The DC-DC converter includes a main converter output stage connected in parallel with an auxiliary output stage. The main output stage is responsible for steady-state operation and is designed to achieve high conversion efficiency using large inductor and power transistors with low on-resistance. The auxiliary stage is responsible for transient suppression and is only active when a load transient occurs. The auxiliary output stage performs well with inductor and power transistors much smaller than those of the main switching stage and thus achieves well balanced power conversion efficiency and dynamic performance with a much smaller area penalty than previously described dual-output-stage converters.

Abstract: Power control circuit with reducing noise and switching loss includes a first gate driver for driving a first switch, an additional gate driver for driving the first switch, and a managing circuit for controlling the first and the additional gate driver to drive the first switch according to a switching signal and turning off the additional gate driver according to a switching voltage on a first end of the first switch, wherein the first end of the first switch is coupled to a load, second end of the first switch is coupled to an input power source, a third end of the first switch is coupled to the first and the additional gate drivers.

Abstract: A control system for a switching DC-DC converter is proposed. The converter includes an input terminal for receiving an input voltage from a source, a control terminal adapted to receive a switching control signal, and an output terminal for providing to a load an output voltage generated from the input voltage according to the control signal. The control system includes detecting means for detecting a reaching condition of a predetermined value by a current provided to the load by the converter and control means for controlling the control signal according to the output voltage. The control system further includes disabling means for disabling the supply of the control signal to the control terminal according to the detection of the reaching condition. The disabling means includes selection means for controlling the disabling according to a time relationship between the detection of the reaching condition and the control signal.

Abstract: A hysteretic power converter wherein an additional adjustment circuit, implemented as an offset correction loop, adds an offset to the comparator detection function to reduce the difference between the average output voltage and the regulation set point voltage. The adjustment circuit lies outside the main hysteretic regulation loop and therefore does not substantially impact the response time of the hysteretic loop, and is slow acting responsive to a low pass filter.

Abstract: A temperature independent type reference current generating device and methods thereof. A temperature independent type reference current generating device may include a first reference current generator generating a first reference current having a first element decreasing according to a temperature, a second reference current generator generating a second reference current having a second element increasing according to the temperature, and/or mirroring and outputting a second reference current and/or a mirrored second reference current. A temperature independent type reference current generating device may include a first current mirror mirroring a first reference current and/or outputting a mirrored first reference current, and a second current mirror adding a mirrored first reference current and a mirrored second reference current, and/or mirroring a result of an addition to output a mirrored result as an output reference current.

Abstract: The present invention relates to an apparatus and method for measuring the critical current of a superconducting tape. A continuous critical current measurement apparatus for measuring critical current of a superconducting tape while feeding a superconducting tape in a liquid nitrogen container includes wheel-type current terminals and wheel-type voltage terminals. The superconducting tape is continuously supplied and fed by a reel-to-reel device, and the critical current of the superconducting tape is measured in real time using the wheel-type current terminals and the wheel-type voltage terminals while the superconducting tape is fed at constant linear velocity in contact with the wheel-type current terminals and the wheel-type voltage terminals.

Abstract: A method of determining a voltage and phase across an electric heating element in a laundry treating appliance, such as a clothes dryer.

Abstract: Two transversely poled fibers are disclosed which can be wound around a holder with their poling directions being anti-parallel. A coupling exchanges the polarization directions of the modes of the fibers. Thermally and mechanically caused birefringence changes can thereby be substantially cancelled, while electrical field induced birefringence changes can be added, to provide a more robust high voltage measuring device.

Abstract: Disclosed is a method for using at least one static probe during polymerization in a fluid bed polymerization reactor system to monitor a coating on a surface of the reactor system and a distal portion of each static probe, wherein the coating is exposed to flowing fluid within the reactor system during the reaction. The surface may be a reactor bed wall (exposed to the reactor's fluid bed) and the coating is exposed to flowing, bubbling fluid within the fluid bed during the reaction. The method may include steps of: during the polymerization reaction, operating the static probe to generate a sequence of data values (“high speed data”) indicative of fluid flow variation (e.g., bubbling or turbulence), and determining from the high speed data at least one electrical property of the coating (e.g., of a portion of the coating on the distal portion of the static probe).

Abstract: The present invention relates to a proximity sensor having a first transmission coil, a second transmission coil, at least one reception coil, an excitation device which is connected to the first and second transmission coils, and an evaluation unit which is connected to at least one transmission coil and/or to the excitation device as well as to the at least one reception coil.

Abstract: The object of the invention is to provide a rotational angle measurement apparatus that is capable of correcting an error due to pin-angle error with a small amount of calculation operation. The rotational angle measurement apparatus includes a magnetic sensor 301 and a signal processing unit 303M. The magnetic sensor includes two bridges comprising magneto-resistance elements each having a pinned magnetic layer. A ratio-calculation unit 381 of the signal processing unit 303M calculates a ratio Vy/Vx of output signals Vx and Vy. A parameter correction unit 382 subtracts a predetermined correction parameter ? from the ratio Vy/Vx calculated by the ratio-calculation unit. An a tan-processing unit 383 conducts arctangent processing on the value calculated by the parameter correction unit and calculates an angle of magnetic field ?.

Abstract: A measuring apparatus includes: a measuring circuit configured to carry out predetermined processing for the measurement result of an object to be measured; a communication control circuit configured to generate output data to be output externally depending on the processing result of the measuring circuit; a power source circuit having a charging element configured to supply power to the measuring circuit and the communication control circuit; an output circuit having open-drain output terminals configured to externally output the output data generated in the communication control circuit; and a charge control circuit configured to charge the charging element at the timing when the output data is not output externally, the open-drain output terminals of the output circuit being used as the input terminals thereof.

Abstract: An encoder to be mounted to a shaft extending from a piston meter configured to compute a volume of distributed fluid includes a magnet affixed to the shaft via a floating magnet holder, a magnetic sensor configured to sense the flux density and direction of a magnetic field created by the magnet and to output a signal indicating the flux density and direction of the magnetic field to a printed circuit board, and the printed circuit board configured to output a signal indicating the volume of distributed fluid if the encoder has not been tampered with and configured to output an error signal if the encoder has been tampered with.

Abstract: A thermoelectrically cooled GMR sensor having a first thermoelectric layer with an array of nanowires, wherein the nanowires include a diameter of about 1 nanometer to about 1000 nanometers. A plurality of alternating layers of magnetic and nonmagnetic material are positioned over and extend the nanowires to form a GMR assembly. A second thermoelectric layer is positioned over the GMR assembly and extends the nanowires, such that the nanowires have a length of between about 100 nanometers and about 500 microns. Conductors are placed in contact with the first and second thermoelectric layers for connecting the thermoelectric layers to a voltage source.

Abstract: A magnetic resonance based apparatus capable of measuring, without using time-of-flight measurements, flow regimes of multi-phase fluids in a pipe, comprises a magnetic resonance module through which the fluid phases flow, wherein the magnetic resonance module includes a radiofrequency coil for transmitting and detecting a signal and means for generating inside the module a homogenous constant magnetic field Bx that is thermally compensated and a transverse magnetic field gradient Gx that is superposed on Bx; and at least one pre-polarization module through which the fluid phases flow before entering the magnetic resonance module.

Abstract: A sequence of magnetic resonance images of the beating heart depicts the flow of blood through the heart chambers. Blood appears bright and background tissues are darkened by acquiring MR data following a preparatory pulse sequence in which spin magnetization throughout the field of view is inverted using a non-selective RF inversion pulse and spin magnetization in a selected pool of blood moving into the heart is re-inverted by a selective RF inversion pulse.

Abstract: A radio frequency (RF) coil array includes a plurality of RF coil sections arranged in a superior-inferior direction. Each RF coil section includes a first linear coil element, a loop-saddle coil quadrature pair and a second linear coil element configured in an overlapping arrangement in a left-right direction. The position of the first linear coil element and the second linear coil element on the left and right may be shifted in the superior-inferior direction with respect to the center loop-saddle coil quadrature pair.

Abstract: A magnetic resonance coil comprises a first set of coil elements (54, 56, 80) operatively connectable with a transmit channel (66, 74) to couple with a transmit region of sensitivity for a selected load at a magnetic field strength greater than 3 Tesla, and a second set of coil elements (52, 54, 82) operatively connectable with a receive channel (66, 74) to couple with a receive region of sensitivity for the selected load at the magnetic field strength greater than 3 Tesla. The first set of coil elements is arranged proximate to but not surrounding the transmit region of sensitivity, and the second set of coil elements is arranged proximate to but not surrounding the receive region of sensitivity. The first set of coil elements and the second set of coil elements having at least one coil element (52, 56) not in common.

Abstract: A transmit-receive switching circuit is offered which is for use in an NMR spectrometer that employs a solid-state NMR probe using a cooled detection coil. The switching circuit is cryogenically cooled to reduce thermal noise in use. The switching circuit has a first terminal for applying high-power RF pulses sent in from the power amplifier of the NMR spectrometer, a second terminal for sending the RF pulses applied from the first terminal to the NMR detector via crossed-diodes and for receiving and entering a low-power NMR signal detected by the NMR detector, and a third terminal for sending the NMR signal entered from the second terminal toward a preamplifier. Plural stages of shunts are connected to the transmission line connecting the second and third terminals such that one stage of shunt corresponds to a 90° phase shift in the RF radiation.

Abstract: A method for determining orientation of an electrically conductive formation proximate an electrically substantially non-conductive formation includes measuring multiaxial electromagnetic induction response within the substantially non-conductive formation using an instrument disposed in a wellbore drilled through the formations. A difference from zero conductivity is determined for each component measurement of the multiaxial electromagnetic induction response. The differences are used to correct the measured response of each component measurement in the electrically conductive response. The corrected component measurements are used to determine the orientation of the conductive formation.

Abstract: A method of predicting an electrochemical mapping parameter in a vehicle that derives at least a portion of its motive power from an energy storage system is provided. The method may comprise providing a plurality of electrochemical mapping parameter sources capable of rendering one or more electrochemical mapping parameters selected from the group consisting of resistance and capacitance and selecting at least one electrochemical mapping parameter source capable of rendering one or more electrochemical mapping parameters based on the state of the energy storage system. The method may also comprise determining an adaptive gain and determining an adaptive factor based on the operating state of the vehicle or the energy storage system. The method may also comprise adapting the one or more electrochemical mapping parameters based on the adaptive factor and adaptive gain to provide an adapted electrochemical mapping parameter value.

Abstract: In a voltage monitor, an abnormality detecting unit receives first information outputted from a first obtaining unit and second information outputted from a second obtaining unit, and determines that an abnormality that affects on at least one of first and second diagnostic thresholds arises in the voltage monitor when the first information is different from the second information. The abnormality detecting unit receives a first forced signal outputted from a first forced-output unit and a second forced signal outputted from a second forced-output unit. The abnormality detecting unit determines whether a timing at which the level of the first diagnostic threshold is switched for each step is deviated from a timing at which the level of the second diagnostic threshold is switched for a corresponding step based on a result of a comparison between the first forced signal and the second forced signal.

Abstract: A detecting station of a winding product and a method for detecting an inter-turn short circuit are provided. The method includes following steps. First, a high voltage pulse is input to two ends of a winding of a winding product. Next, a voltage value of an electrifying process of the winding is extracted for generating an extracting data. Finally, a time-frequency converting operation is performed to the extracting data, and a time-frequency analysis information is generated for indicating whether or not the inter-turn short circuit is occurred in the winding.

Abstract: A method for screening electrolytic capacitors places a capacitor in series with a resistor, applying a test voltage and following the charge curve for the capacitor. A high voltage drop across the capacitor indicates high reliability and a low voltage drop is used to reject the piece. The leakage current is not adversely affected during the test.

Abstract: A sensing circuit for comparing current flow through a reference resistance with current flow through a resistive device under test (DUT) such as a fuse. The sensing circuit includes a comparator having a first PMOS transistor and a first NMOS transistor connected in series between a first input and a first node and a second PMOS transistor and a second NMOS transistor connected in series between a second input and the first node. The first PMOS and NMOS transistors are cross-coupled with the second PMOS and NMOS transistors. Specifically, a first output is connected to the first node to the gates of the second PMOS and second NMOS transistors and a second output is connected to the second node and to the gates of the first PMOS and first NMOS transistors. The reference resistance is connected to one of the inputs and the DUT is connected to the other input.

Abstract: A method for operating an inductive conductivity-measuring cell having a primary circuit with a sending coil, a secondary circuit with a receiver coil, and a short-circuit path, which passes through the sending coil and the receiver coil. The sending coil couples via the short-circuit path inductively with the receiver coil, wherein, in the case of closed short-circuit path, a first electrical signal present in the primary circuit is measured, and wherein the first signal is compared with, and/or weighed against, values, which are furnished or stored.

Abstract: A system for detecting fluid on a substrate is provided. The system includes, but is not limited to, a sensor board, a first capacitive sensor, and a platform upon which the substrate is to be placed. The first capacitive sensor is mounted on the sensor board. The first capacitive sensor has a transmit sensor pad for transmitting a signal, a receive sensor pad for receiving the signal, and an analog-to-digital convertor connected with the receive sensor pad for analyzing the received signal. The platform is a first distance from the transmit and receive sensor pads.

Abstract: The present disclosure relates to a method to determine a characteristic of a subsurface formation using a downhole logging tool. A downhole logging tool having the ability to make substantially concurrent disparate measurements on the subsurface formation is provided and substantially concurrent disparate measurements on the formation using the downhole logging tool are made. Those measurements are used to solve a system of equations simultaneously and the solution to the system of equations is used to determine the characteristic of the subsurface formation.

Abstract: There is provided an alternating current (AC) detection circuit for power supply, the AC circuit including: a rectifying part rectifying an AC voltage; a voltage division part dividing the voltage rectified by the rectifying part according to a preset division ratio; a voltage stabilization circuit part stabilizing the voltage divided by the voltage division part; and a first square wave generating part comparing the voltage stabilized by the voltage stabilization circuit part with an internal reference voltage, and generating a first square wave signal having a duty ratio according to comparison results between the stabilized voltage and the internal reference.

Abstract: A contactor includes: a silicon layer composing a part of beam part with a rear end side provided at a base part and with a front end side sticking out from the base part; SiO2 layer as an insulating layer formed on the silicon layer; and a conductive layer formed on the SiO2 layer.

Abstract: A MEMS probe adapted to contact a corresponding terminal of an integrated circuit, integrated on at least one chip of a semiconductor material wafer during a test phase of the wafer is provided. The probe includes a support structure comprising a first access terminal and a second access terminal; the support structure defines a conductive path between said first access terminal and said second access terminal. The probes further-includes a probe region connected to the support structure adapted to contact the corresponding terminal of the integrated circuit during the test phase for providing at least one test signal received from the first access terminal and the second access terminal to the integrated circuit through at least one portion of the conductive path, and/or providing at least one test signal generated by the integrated circuit to at least one between the first access terminal and the second access terminal trough at least one portion of the conductive path.

Abstract: A testing card for a USB port includes first USB contacting pins, a second USB contacting pin, a transmitting circuits, a voltage converting circuit, and a testing portion. The first USB contacting pins are connected to the USB port to receive a number of USB signals. The second USB contacting pin is connected to the USB port to receive a voltage signal from the USB port. The transmitting circuit is electrically connected to the first USB contacting pins to transmit the USB signals therefrom. The voltage converting circuit is electrically connected to the second USB contacting pin to convert the voltage signal to a predetermined level. The testing portion is electrically connected to the outputs of the transmitting circuit and the voltage converting circuit to receive the USB signals and the converted voltage signal.

Abstract: A manufacturing method of manufacturing a wafer unit for testing includes forming a plurality of test circuits on a circuit wafer, forming a plurality of circuit pads on a predetermined surface of a connecting wafer, forming a plurality of wafer pads on a rear surface of the connection wafer opposing the predetermined surface, forming a plurality of long via holes to electrically connect the plurality of circuit pads and the plurality of wafer pads, and forming the wafer unit for testing, by overlapping the circuit wafer and the connection wafer to electrically connect the plurality of test circuits and the plurality of circuit pads.