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 solid state disk (SSD) power supply system includes power supply switching circuit. The power supply switching circuit comprises a first power input to receive a first direct current (DC) voltage signal, a second power input connected to a super capacitor to receive a second DC voltage signal provided by the super capacitor, a switching chip connected to the first and second power inputs and configured to select the second DC voltage signals to output in a situation that the first power input is disabled to receive the first DC voltage signal, a voltage converting chip to receive the voltage signal output from the switching chip, and a voltage output to output an operation voltage to an SSD according to the voltage signal. The switching chip and the voltage converting chip respectively output a first and second test signals for testing a discharging time of the super capacitor.

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 power switch circuit includes a control circuit, and first and second detecting circuits. The control circuit includes first and second field effect transistors (FETs) and first and second sensing resistors. The first detecting circuit includes two input terminals connected to the first and second ends of the first sensing resistor and an output terminal connected to the first FET. The first detecting circuit controls the first FET to be turned on or turned off according to the voltages of the first and second ends of the first sensing resistor. The second detecting circuit includes two input terminals connected to the first and second ends of the second sensing resistor and an output terminal connected to the second FET. The second detecting circuit controls the second FET to be turned on or turned off according to the voltages of the first and second ends of the second sensing resistor.

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 measurement card includes a circuit board, an edge connector on a bottom edge of the circuit board, a port arranged on the circuit board, and a single-pole double-throw switch for connecting the port to either a first or a second pin of the edge connector to tests the VDDQ and VTT outputs of a memory slot.

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 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 balancing resistor testing apparatus is configured for acquiring a resistance of a balancing resistor electronically connected to a supercapacitor of a series supercapacitor assembly in parallel. The balancing resistor testing apparatus includes a controller and a digital potentiometer. The controller detects a voltage across each supercapacitor of the series supercapacitor. The digital potentiometer comprising a plurality of variable resistors each of which is electronically connected to a supercapacitor in parallel, the controller controls the digital potentiometer to continuously adjust the effective resistance of each potentiometer until the controller detects that each supercapacitor has the same or very similar voltage.

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 circuit for alarming abnormal state of a computer fan includes a detection circuit coupled to the computer fan, a controller coupled to the detection circuit and the computer fan, an alarm unit coupled to the controller. The detection circuit detects a power source and a speed control signal received by the computer fan, the controller determines the work state of the computer fan according to the power source, the speed control signal, and a speed signal received from the computer fan and raises an alarm through the alarm unit if the computer fan is not working normally.

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 security system and method for an electronic device include comparing data in a Subscriber Identity Module (SIM) card with data in a virtual SIM card, if the virtual SIM card is not blank. The security system further include determining whether the electronic device has received a command of reporting loss of the SIM card from the network server, if the data in the SIM card is the same as the data in the virtual SIM card. The security method further includes running the electronic device normally if the electronic device has not received the command of reporting loss of the SIM card. If the command of reporting loss is received, a contact list and message of the electronic device are deleted and a calling function of the electronic device is disabled.

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 keyboard includes a number of first keys, a control circuit, a switch circuit, and a second key. The switch circuit includes a number of switches. The second key is connected to first terminals of two switches of the switch circuit via the control circuit. A second terminal of each of the switches is connected to a first key. When a second key is pressed, the control circuit controls the switches corresponding to the pressed second key to be turned on, to activate the first keys which are connected to the switches.

Abstract: A power cable is configured for connecting at least one electrical device to a power source. The power cable includes an input terminal, at least one output terminal, a power transmitting wire, a switch, a voltage setting device, a voltage sampling device, a voltage comparing device and a power supply. The power transmitting wire connects the input terminal and the output terminal via the switch. The voltage sampling device is configured for sensing a voltage of the output terminal. The voltage comparing device is configured for comparing a preset voltage stored in the voltage setting device and the sampled voltage sensed by the voltage sampling device to turn on or turn off the switch according to the compared result. The power supply is configured for reducing the voltage of the power source to the rated voltage of the voltage comparing device to power the voltage comparing device.

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.