Abstract: A wireless unlocking system includes a programmable telephone. When the programmable telephone receives a call from a communication terminal along with a calling telephone number, the calling telephone number is matched with a number of pre-stored telephone numbers. The programmable telephone transmits an unlocking signal to an electrically controlled lock and unlocks a door if the telephone number of the call successfully matches one of the pre-stored telephone numbers.

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 sequence control circuit for power sources includes two switched circuits and a sequence control unit. Each of the switched circuits has a control node and is coupled between a power source and a load. The sequence control unit includes two output terminals coupled to the control nodes. The output terminals generate control signals to control the sequence of the circuits being turned on.

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.

Abstract: A wireless unlocking system includes a programmable telephone. When the programmable telephone receives a call from a communication terminal along with a calling telephone number, the calling telephone number is matched with a number of pre-stored telephone numbers. The programmable telephone transmits an unlocking signal to an electrically controlled lock and unlocks a door if the telephone number of the call successfully matches one of the pre-stored telephone numbers.

Abstract: An input power measuring device includes a board with an edge connector, a first dual inline memory modules (DIMM) socket, a resistor, a differential amplifier circuit, a voltage dividing circuit, a display screen, and a controller. When the edge connector is inserted into a second DIMM socket of a motherboard and the motherboard is powered on, the resistor samples first current, and converts the first current into a first voltage. The differential amplifier circuit amplifiers the first current to a second current. The voltage dividing circuit divides the first voltage, and outputs a second voltage. The controller converts the second current into a third current, converts the second voltage into a third voltage, and calculates a power according to the third current and the third voltage.

Abstract: A driver circuit drives a pulse width modulation (PWM) controller. The driver circuit includes an enabling circuit, a power supply input control circuit, a stabilizing circuit, and a discharge circuit. The stabilizing circuit is electrically connected to the PWM controller. The power supply input control circuit is electrically connected between the enabling circuit and the stabilizing circuit. The discharge circuit is electrically connected between the stabilizing circuit and the ground. In response to the driver circuit working in normal operation, the enabling circuit enables the power supply input control circuit to output a working voltage to the stabilizing circuit, and in response to the process of the driver circuit restarting, the enabling circuit enables the power supply input to stop outputting power supply to the stabilizing circuit. The discharge circuit leads a residual voltage of the stabilizing circuit to the ground, during the process of the driver circuit being restarted.

Abstract: A wireless remote control device for controlling an electronic device includes a switch module, a wireless transmission module, a wireless receiving module and a control module. The switch module receives a DC voltage and outputs a first control signal. The wireless transmission module receives the first control signal and encodes the first control signal to output an encoded first control signal. The wireless receiving module receives the encoded first control signal and decodes the encoded first control signal to output a decoded first control signal. The control module receives the decoded first control signal and outputs a second control signal to turn on/off or reset the electronic device.

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 capacitor test fixture for positioning capacitors under test includes a main body, a clamping section, an operating section, and a cover. The main body defines an opening, a plurality of receiving slots at the bottom of the opening to receive the capacitors, some positioning slots located at opposite sides of the opening, and a sliding slot. The clamping section includes a first hook, and the operating section includes a second hook corresponding to the first hook. The cover locates and fixes the clamping section and the operating section to the main body. The operating section functions when the second hook holds back the first hook, the capacitors under test are received within the receiving slots, and when the second hook releases the first hook, the clamping section secures and makes contact with the capacitors for testing.

Abstract: An adjusting device adjusts a load line of a CPU power supply circuit. The adjusting device includes a controller, a DC electronic load device, a voltage follower, an adjustable resistor, and an indicator. The controller controls the DC electronic load device to change an output current of the circuit. The voltage follower sends an output voltage of the circuit to the controller. The controller calculates the load line of the circuit based on the output current and the output voltage of the circuit, determines whether the load line satisfies the required value, changes a resistance of the adjustable resistor until the load line satisfies the required value, and sends a resistance of the adjustable resistor to the indicator.

Abstract: A resistance determining system is used to determine an offsetting resistance of a mainboard to establish a predetermined offset voltage. The system includes an input equipment, a single-chip, and a resistor. The input equipment sets a predetermined standard voltage of the mainboard. The resistor supplies the mainboard with various resistances, to adjust real output voltage of the mainboard. The single-chip monitors the real output voltage of the mainboard, and adjusts the resistance of the resistor until the difference between the real output voltage and the predetermined standard voltage is equal to a predetermined offset voltage.

Abstract: A protocol resolution device electrically connected to a central processing unit (CPU) includes a signal controller to receive communication protocol from the CPU, a signal input module, and display module. The signal input module provides an electrical signal to the signal controller. The signal controller decodes the communication protocol from the CPU and stores the decoded communication protocol, the signal controller selectively accesses and calls up the decoded communication protocol according to the electrical signal, and transmits the decoded communication protocol to the display module for display.

Abstract: A driving circuit includes a switching circuit, an acquiring circuit, an amplifying circuit, and an adjusting circuit. The switching circuit includes a driving chip and a switching unit. The switching unit is connected between a power source and a load, the driving chip is configured for controlling the connection and disconnection of the switching unit. The acquiring circuit is connected between the switching unit and the load, and is configured for providing a feedback to the amplifying circuit. The amplifying circuit includes two amplifying input terminals connected to two terminals of the acquiring circuit and an amplifying output terminal outputting an amplified voltage. The adjusting circuit is connected to the amplifying output terminal and is configured for outputting different control voltages to the driving chip according to the amplified voltage. The driving chip outputs different driving voltages to the switching unit according to the control voltages.

Abstract: A mobile phone includes a fingerprint input unit, a storage unit, a switch unit, and a control unit. The fingerprint input unit is used to read and record fingerprint information of a user, and output the fingerprint information. The storage unit stores a fingerprint mode. The switch unit is connected to a power on/off terminal of the mobile phone. The control unit is used to receive the fingerprint information and compare the received fingerprint information with the stored fingerprint mode. If the received fingerprint information is not consistent with the stored fingerprint mode and the mobile phone is at a power-off state, the control unit outputs a first control signal to control switch unit to keep the mobile phone being at the power-off state.

Abstract: An ON/OFF detection circuit for detecting an electronic device includes a switch circuit, a current sampling circuit, an amplifying circuit, and a control circuit. The switch circuit includes an input terminal connected to a constant voltage source, an output terminal coupled to the electronic device, and a control terminal. The current sampling circuit is connected between the input terminal and the output terminal of the switch circuit, and is configured for sampling current flowing to the electronic device and converting sampled current into sampled voltage. The amplifying circuit is configured for filtering and amplifying the sampled voltage. The control circuit controls the ON and OFF of the electronic device and compares the sampled voltages with a comparison voltage to judge the electronic device is qualify or disqualify.

Abstract: A power supply conversion circuit includes a PWM chip and many sub-circuits. Each sub-circuit includes an inductor, a first capacitor connected to ground, a first resistor connected in series with the first capacitor to form a branch parallel to the inductor, a differential pair having a first differential signal trace and a second differential signal trace, a second resistor, and a second capacitor. The first trace is connected between the connection of the first resistor and the first capacitor and the PWM chip. The second resistor is connected between the connection of the first resistor and the inductor and the second capacitor. The second trace is connected between the connection of the second resistor and the second capacitor and the PWM chip. The ratios of the capacitances of each two second capacitors are the same as that of the lengths of the traces of each two corresponding differential pairs.

Abstract: A resistance determining system and method for a protection circuit, includes a resistance determining unit. The resistance determining unit interconnects a microcontroller and a digital resistor, where the microcontroller has first setting voltage corresponding to a first voltage threshold for activating the protection circuit, and the microcontroller is capable of receiving and converting a first external voltage input to the protection circuit to be a first converted voltage. The digital resistor includes a first variable resistor having two terminals connected to the respective first terminal and the second terminal. The microcontroller adjusts a resistance of the first variable resistor to be a first threshold resistance if the first converted voltage is substantially equal to the first voltage threshold, and the first resistance is determined to be substantially equal to the first threshold resistance.

Abstract: A server rack includes a main body, an electronic scale, and an alarm. The main body is used for receiving a number of servers. The electronic scale includes a pressure sensor and a microcontroller. The main body presses on the pressure sensor so that the pressure sensor can measure the pressure from the main body to obtain a pressure signal. The microcontroller analyzes the pressure signal to calculating the total weight of the main body and the servers. The alarm stores a predetermined weight threshold, which is the total weight of the main body and the maximum servers that the main body can bear. The alarm also compares the measured total weight with the predetermined weight threshold. When the measured total weight is larger than the predetermined weight threshold, the alarm alarms.