Abstract: A measurement circuit includes a switch unit with a number of keys selectively pressed to output different resistance regulating signals. A resistance setting circuit receives the resistance regulating signals and connects different resistances to a voltage circuit and a current circuit. The voltage circuit outputs different voltages. The current voltage receives a voltage from the voltage circuit and outputs a current to a capacitor. A detecting circuit measures a temperature of the capacitor and outputs the temperature to the resistance setting circuit. The resistance setting circuit compares the received temperature with a preset temperature. If the received temperature is equal to or greater than the preset temperature, the resistance setting circuit outputs short-circuit information of the capacitor. If the received temperature is less than the preset temperature, the resistance setting circuit outputs normal information of the capacitor. A display unit displays the information of the capacitor.

Abstract: An electrical parameter detection device is configured for detecting electrical parameters of a peripheral component interconnect (PCI) connector including a plurality of power pins. The electrical parameter detection device includes a processor module, a first detection module, and a second detection module. The processor module continuously detects voltage values of electric potentials provided by each of the power pins of the PCI connector using the first detection module, and determines time sequences of the electric potentials according to the voltage values of the electric potentials. Furthermore, the processor module detects the amount of power provided by each of the power pins of the PCI connector using the second detection module.

Abstract: A power supply device is configured for supplying electrical power to a central processing unit (CPU) of an electronic device. The CPU operates in a number of working modes. The power supply device includes a power supply module operating in a number of power supply modules corresponding to the working modes of the CPU, a number of compensation circuits respectively corresponding to the power supply modes, and a control module. The control module determines the working mode of the CPU and controls the corresponding compensation circuit to electrically connect to the power supply module to provide a loop compensation to the power supply module which improves stability and responding speed of the power supply module.

Abstract: A voltage regulating device includes a connector, a slot, a voltage regulating circuit, and a control module. The connector is obtains an initial voltage from an external power supply. The slot is configured for electrically connecting to a load. The voltage regulating circuit is connected between the connector and the slot. In accordance with user input into a keyboard connected to a control microchip as to a voltage level required, the voltage regulating circuit converts the initial voltage to a required test voltage and outputs the required test voltage to the load by the slot. The control microchip controls the voltage regulating circuit to convert the initial voltage into the required test voltage.

Abstract: A capacitance measurement circuit includes a charge module to charge a capacitor, a discharge module to hold the capacitor discharge at a constant current, and a control module. The control module includes a timer, a detecting sub-module, a trigger sub-module, and a computing sub-module. The detecting sub-module detects whether the capacitance is fully charged and detects voltages V and discharge current I when the capacitor discharges. The trigger sub-module triggers the charge module to stop charging the capacitor and triggers the timer starts to time a preset discharge time once the capacitor is fully charged. The computing sub-module computes any output voltage differences during the discharge time, and further computes the capacitance value of the capacitor.

Abstract: A resistance determining device configured for determining a resistance for a digital power supply control microchip includes a digital potentiometer and a controller. The digital potentiometer is electrically connected to the digital power supply control microchip. The controller is electrically connected to the digital potentiometer. The controller obtains internal current and load current of the digital power supply control microchip, compares the internal current with the load current, and changes a current resistance of the digital potentiometer to be a resistance according to a difference between the internal current and the load current. The resistance makes the internal current consistent with the load current.

Abstract: An apparatus is configured for calibrating a test value of an output current of a digital power supply. The power supply has a control chip configured for detecting and outputting the test value of the output current. The apparatus includes a keyboard circuit, a digital potentiometer and a controller. The keyboard circuit is configured for inputting an actual value of the output current. The digital potentiometer is electronically connected to the control chip. The controller receives a test value and the actual value of the output current respectively from the control chip and the keyboard, determines whether the test value is equivalent to the actual value, adjusts the test value of the output current by adjusting an effective resistance of the digital potentiometer until the test value equals the actual value, and outputs the effective resistance of the digital potentiometer when the test value equals the actual value.

Abstract: A monitored device is used to monitor power parameters of a memory bank of a computing device. The monitoring device includes a main circuit board, a connector, and a parameter monitoring device. The parameter monitoring device comprises an acquisition unit, a processing unit, and a display unit. The main circuit board is connected to a power supply and providing power signals to one or more power pins of the memory bank. The connector is connected between the main circuit board and the memory bank. The acquisition unit acquires a voltage passing through each power pin of the memory bank when power is supplied to the memory bank. The processing unit processes the voltage acquired from each of the one or more power pins to obtain power parameters of the memory bank. The display unit displays the power parameters of the memory bank.

Abstract: A monitor device is used to monitor power parameters of a CPU of a computing device. The monitoring device comprises a main circuit board, a connector, and a parameter monitoring device. The parameter monitoring device comprises an acquisition unit, a processing unit, and a display unit. The main circuit board is connected to a power supply and provides power signals to one or more power pins of the CPU. The connector is connected between the main circuit board and the CPU. The parameter monitoring device is connected to the CPU through the connector. The acquisition unit acquires a voltage passing through each power pin of the CPU after the CPU is powered to work. The processing unit processes the voltage acquired from each of the one or more power pins to obtain power parameters of the CPU. The display unit displays the power parameters.

Abstract: A printed circuit board (PCB) includes two power supply units, a central processing unit (CPU), two inductors and a temperature compensation resistor. One of the inductor is electrically connected between one power supply unit and the CPU, the other inductor is electrically connected between another power supply unit and the CPU. The temperature compensation resistor is electrically connected between the power supply units and ground, and is positioned between the two inductors to adjust output voltage from the CPU.

Abstract: A buck converter includes a power supply unit, two MOSFETs and a delay circuit. The PWM module is coupled to the gates of the two MOSFETs to alternatively turn on the two MOSFETs. The delay circuit is coupled between an output terminal and an input node of the PWM module for making sure that a voltage applied to the PWM module is after a voltage applied to a drain the MOSFETs.

Abstract: A multimeter includes a main body, two probes extending from the main body, a battery unit arranged in the main body, and a charging system arranged in the main body and configured for charging the battery. The charging system includes a microcontroller with an external input voltage sampling circuit, a battery voltage sampling circuit and a voltage regulator circuit each electrically connected the microcontroller. The microcontroller compares sampled signals from the external input voltage sampling circuit and the battery voltage sampling circuit, and controls the voltage regulator circuit to regulate the external input voltage to be applicable to the battery based on the comparison.

Abstract: A power measuring system for measuring a turning-on power, a turning-off power, and a turned-on power of a first field-effect transistor includes a pulse driver, a first resistor, a processing unit, and an indication unit. The pulse driver generates square wave signals. The processing unit samples voltages at the source and the drain of the first field-effect transistor, and at the first and second terminals of the first resistor at the moment when the square wave signals changes from low to high or from high to low, and calculates the turning-on power, the turning-off power, and the turned-on power of the first field-effect transistor. The indication unit displays the turning-on power, the turning-off power, and the turned-on power of the first field-effect transistor.

Abstract: A resistance determining system for an over voltage protection (OVP) circuit, includes an external power source, a microcontroller, a digital rheostat and a display unit. The external power source supplies an external voltage to the OVP circuit. The microcontroller stores an over voltage value. The microcontroller is connected to the external power source and configured to detect the external voltage and compare the external voltage with the over voltage value. The digital rheostat is connected to the microcontroller and includes a first rheostat having two connection terminals respectively connected to two first connection ends of the OVP circuit. The microcontroller adjusts the first rheostat to be a first resistance value to activate the OVP circuit when the external voltage is substantially equal to the over voltage value. The display unit is connected to the microcontroller and configured to display the first resistance value.

Abstract: A detection device to detect a power serving time of a super capacitor for a power-disconnected storage card and an amount of the data packets capable of being stored during the detected serving time is provided. The power-disconnected storage card includes a memory. The detection device includes a power supply unit, the super capacitor, a controller, a storage unit, and a detection unit. The storage unit stores the data packets. The detection unit includes a charge notification module, a data notification module and a time module. The charge notification module generates a first notification signal to the time module. The data notification module generates a second notification signal to the time module when the storage unit transmits the data packet to the memory. The time module records time when the memory completely store the data packet according to the first notification signal and the second notification signal.

Abstract: A computer memory device includes a circuit board, a number of chips mounted on a surface of the circuit board, and an edge connector set on a bottom side of the circuit board. The edge connector includes ground pins, power pins, and data pins. Top ends of the ground pins, the power pins, and the data pins are in alignment with one another. Each ground pin is longer than each of the power pins and the data pins.

Abstract: A power supply circuit includes a pulse width modulation (PWM) chip, a number of phase circuits, a voltage output end, and a spike suppression circuit. The spike suppression circuit is connected to each of the phase circuits and the voltage output end. The PWM chip controls all of the phase circuits to alternately output power supply voltages according to a predetermined sequence. The spike suppression circuit receives the power supply voltages, and filters out voltage spikes in the power supply voltages, thereby outputting steady voltages to the voltage output end.

Abstract: An output voltage adjustment circuit for buck circuits includes a microcontroller, first to eighth keys, and a display unit. The first to eighth keys input voltage adjustment signals to the microcontroller. A first input pin of the microcontroller is connected to a voltage output terminal. A second resistor is connected between the first input pin of the microcontroller and ground. A first to a sixth input/output pin of the microcontroller are connected to the display unit. A first to an eighth output pin of the microcontroller are connected to a pulse width modulation (PWM) controller. The first to eighth keys are selectively activated to provide voltage adjustment signals to the microcontroller, sampling output voltages of the voltage output terminal, comparing with a predetermined voltage, controlling the PWM controller to fine tune the duty cycle to output a stable voltage from the voltage output terminal. The display unit displays the voltages on the voltage output terminal.

Abstract: A circuit for measuring the DC resistance of an inductor includes an input unit, a microprocessor module, a current source and a voltage detecting unit. The microprocessor module receives signals from the input unit and generates different signals to command constant currents through the inductor by the current source. The voltage detecting unit reads voltages of the inductor and outputs the voltages obtained to the microprocessor module. According to the currents and the voltages read, the microprocessor module may calculate the DC resistance(s) of the inductor.

Abstract: A power circuit which is applicable to a data storage device. A boost circuit receives a first voltage and converts it to a second voltage. A charging and discharging circuit receives the second voltage and charges a charging capacitor. As long as a voltage detecting circuit detects that the second voltage exists, it outputs a first selection signal. When the voltage detecting circuit detects that the second voltage does not exist, it outputs a second selection signal and also outputs a signal to the charging and discharging circuit, to release a stored voltage. A voltage selection circuit will output the second voltage according to the first selection signal, or will output the stored voltage from the charging capacitor according to the second selection signal. Buck circuits convert the second voltage or the stored voltage to the different voltages required by a control chip of the data storage device.