Abstract: A computer system includes a display, a motherboard and a power circuit. The display includes a video interface. The motherboard includes a super input-output (SIO) chip. The power circuit includes a first switch unit, a second switch unit, a third switch unit, and an oscillator. When the display is powered on, the video interface outputs a high level signal, the first switch unit is turned on, a power supply powers the oscillator through the first switch unit. The oscillator operates and outputs a high level signal, the second switch unit is turned on, a power-on signal pin of the SIO chip receives a low level signal, and the motherboard is turned on.

Abstract: A computer system includes a power supply unit (PSU), a matching circuit, and a chip. The matching circuit includes a voltage conversion unit, a voltage-dividing unit, a first resistor, a comparator, a diode, and a delay unit. The comparator includes a non-inverting terminal electrically coupled to the PSU to receive a power-good signal, an inverting terminal electrically coupled to the voltage-dividing unit to receive a reference voltage, and an output terminal. The delay unit is electrically coupled to a power supply and a power-good signal pin of the chip. When a voltage of the power-good signal is greater than the reference voltage, the output terminal of the comparator outputs a high level signal, the diode is turned off and the power supply is delayed by the delay unit and then output to the power-good signal pin of the chip.

Abstract: A power circuit for an electronic device includes an input terminal, an output terminal, a voltage transform unit, and a control unit. The control unit controls the voltage transform unit to operate or not operate, according to the input terminal receives a first voltage or a second voltage. The first voltage is transformed to an output voltage, and is output by the output terminal, when the input terminal receives the first voltage. The second voltage is transmitted from the input terminal to the output terminal through the third switch unit, when the input terminal receives the second voltage. Therefore, the power circuit can receive the first voltage or the second voltage through the input terminal, and outputs the output voltage to other electronic components.

Abstract: A power circuit for an electronic device includes an input terminal, an output terminal, a voltage transform unit, and a control unit. The control unit controls the voltage transform unit to operate or not operate, according to the input terminal receives a first voltage or a second voltage. The first voltage is transformed to an output voltage, and is output by the output terminal, when the input terminal receives the first voltage. The second voltage is transmitted from the input terminal to the output terminal through the third switch unit, when the input terminal receives the second voltage. Therefore, the power circuit can receive the first voltage or the second voltage through the input terminal, and outputs the output voltage to other electronic components.

Abstract: A computer system includes a power supply unit (PSU), a matching circuit, and a chip. The matching circuit includes a voltage conversion unit, a voltage-dividing unit, a first resistor, a comparator, a diode, and a delay unit. The comparator includes a non-inverting terminal electrically coupled to the PSU to receive a power-good signal, an inverting terminal electrically coupled to the voltage-dividing unit to receive a reference voltage, and an output terminal. The delay unit is electrically coupled to a power supply and a power-good signal pin of the chip. When a voltage of the power-good signal is greater than the reference voltage, the output terminal of the comparator outputs a high level signal, the diode is turned off and the power supply is delayed by the delay unit and then output to the power-good signal pin of the chip.

Abstract: A computer system includes a display, a motherboard and a power circuit. The display includes a video interface. The motherboard includes a super input-output (SIO) chip. The power circuit includes a first switch unit, a second switch unit, a third switch unit, and an oscillator. When the display is powered on, the video interface outputs a high level signal, the first switch unit is turned on, a power supply powers the oscillator through the first switch unit. The oscillator operates and outputs a high level signal, the second switch unit is turned on, a power-on signal pin of the SIO chip receives a low level signal, and the motherboard is turned on.

Abstract: A power on circuit is connected between a video graphics array (VGA) connector of a display and a super input output (SIO) chip of a motherboard. The power on circuit includes first to fourth electronic switches and a timer. When a power button of the display is pressed, a serial data line pin of the VGA connector outputs a high level signal to turn on the first electronic switch, the second electronic switch is turned on, the fourth electronic switch is turned on, and the timer outputs a periodic pulse signal. When the pulse signal outputted from the timer is at a high level, the third electronic switch is turned on, the SIO chip receives a low level signal from the fourth and third electronic switches, and the motherboard is turned on.

Abstract: A charging circuit is used to charge a rechargeable battery. The charging circuit includes a voltage conversion unit and a leakage prevention unit. The voltage conversion unit converts a voltage of a power supply into a charging voltage of the rechargeable battery, and outputs the charging voltage to the leakage prevention unit. When the leakage prevention unit receives the charging voltage, the leakage prevention unit charges the rechargeable battery with the charging voltage. When the leakage prevention unit does not receive the charging voltage, the leakage prevention unit prevents a leakage of the rechargeable battery.

Abstract: A charging circuit is used to charge a rechargeable battery. The charging circuit includes a voltage conversion unit and a leakage prevention unit. The voltage conversion unit converts a voltage of a power supply into a charging voltage of the rechargeable battery, and outputs the charging voltage to the leakage prevention unit. When the leakage prevention unit receives the charging voltage, the leakage prevention unit charges the rechargeable battery with the charging voltage. When the leakage prevention unit does not receive the charging voltage, the leakage prevention unit prevents a leakage of the rechargeable battery.

Abstract: An interface detection circuit is used for detecting whether an interface of an electronic device is in good contact with an interface of a connection device. The interface detection circuit includes a pressure sensing module, a signal processing module, and a warning module. The pressure sensing module detects whether the pins of the interface of the electronic device is suffered pressure and transmits the detecting results to the signal processing module. The signal processing module magnifies and calculates the detecting results. The signal processing module outputs a control signal to the warning module. The warning module alerts the user whether the two interfaces make good contact with each other.

Abstract: A test device for testing an electronic device, includes an alternating current (AC) input port used to connect to an AC power source. An AC output port used to connect to a power port of the electronic device, a switch unit connected between the AC input port and the AC output port, a first USB port, a startup control unit, and a power on maintaining unit. The switch unit is used to establish a connection between the AC input port and the AC output port, or to cut off the connection. The first USB port connects to a second USB port of the electronic device. The startup control unit turns on the switch unit after the electronic device is turned off for a predetermined time. The power on maintaining unit maintains the switch unit to turn on after the electronic device is turned on.

Abstract: An indicating circuit for indicating the rotation speed of a fan includes a rotation speed indicating module connected to the fan and receiving rotation speed signals from the fan. The indicating circuit includes a switch and a light emitting element. If the received signal is a high level signal, the switch is turned on, and the light emitting element emits light. If the reeived signal is a low level signal, the switch is turned off, and the light emitting element does not emit light.

Abstract: A power on circuit is connected between a video graphics array (VGA) connector of a display and a super input output (SIO) chip of a motherboard. The power on circuit includes first to fourth electronic switches and a timer. When a power button of the display is pressed, a serial data line pin of the VGA connector outputs a high level signal to turn on the first electronic switch, the second electronic switch is turned on, the fourth electronic switch is turned on, and the timer outputs a periodic pulse signal. When the pulse signal outputted from the timer is at a high level, the third electronic switch is turned on, the SIO chip receives a low level signal from the fourth and third electronic switches, and the motherboard is turned on.

Abstract: A short circuit detection device is provided to check a circuit layout. The circuit layout includes electronic components connected in parallel. Any of the electronic components includes two contacts on the circuit layout. The short circuit detection device includes a determination circuit configured to determine whether a short circuit has occurred in the circuit layout, and a detection circuit configured to determine the specific electronic component or components responsible for the short circuit. The determination circuit connects with one contact of any of the electronic components. The detection circuit connects with two contacts of any of the electronic components.

Abstract: A voltage measurement apparatus includes a power interface, first and second voltage detecting modules, first and second driving modules, and first and second indication modules. The first voltage detecting module compares an output voltage with a first reference voltage, to determine whether the output voltage is greater than the first reference voltage. The second voltage detecting module compares the output voltage with a second reference voltage, to determine whether the output voltage is less than the second reference voltage. The first indication module indicates the output voltage when the output voltage is greater than the upper limit voltage or less than the lower limit voltage. The second indication module indicates the output voltage when the output voltage is less than or equal to the upper limit voltage and greater than or equal to the lower limit voltage.

Abstract: An indicator light control circuit for controlling a single indicator light to indicate a high or low link speed of a network connection includes a pulse signal generating circuit, a bias circuit having a digital potentiometer, and a controller. The pulse signal generating circuit generates a pulse signal. The digital potentiometer is electronically connected to the pulse signal generating circuit and the controller. The controller adjusts the effective resistance of the digital potentiometer connected to the pulse signal generating circuit according to different link speeds being experienced in the network connection, to adjust a duty cycle of the pulse signal, thereby changing the on-time and off-time of the indicator light.

Abstract: An overvoltage protection circuit includes a power device for outputting a plurality of first powers, a plurality of VRMs for respectively receiving the plurality of first powers, a plurality of voltage dividing circuits, a reference power supply for outputting a reference voltage, and a comparison circuit having a comparator. Each VRM converts a corresponding first power to a regulated second power. The plurality of voltage dividing circuits respectively divides voltages of the second powers, each voltage dividing circuit outputs a divided voltage. The comparator compares a combination of the divided voltages with the reference voltage, and when an overvoltage occurs in at least one of the second powers, the comparator outputs a control signal via the output terminal to the power device to control the power device to shut down all of the first powers.

Abstract: A protection circuit that protects a load charged by a power supply. The protection circuit includes a reference voltage set circuit, a sampling circuit, a switch, and a comparator. The reference voltage set circuit provides a reference voltage. The sampling circuit is electrically connected to the power supply and provides a sampling voltage based on a charge voltage output from the power supply to the load. The switch is electrically connected between the power supply and the load. The comparator includes a non-inverting input terminal electrically connected to the reference voltage set circuit, an inverting input terminal electrically connected to the sampling circuit, and an output terminal electrically connected to the switch. The comparator compares the sampling voltage with the reference voltage, and controls the switch to turn on or off according to the comparison.

Abstract: A connection circuit for a digital visual interface (DVI) includes a platform controller hub (PCH), a DVI, a plurality of voltage dividing resistors, and a switch. The platform controller hub (PCH) includes a plurality of output contacts outputting a plurality of analog signals. The DVI includes a plurality of input contacts, and each input contact is connected to one of the output contacts to transmit the analog signals. The switch has one end connected to the output contacts, and another end grounded. The switch switches on when a power supply is applied to the switch and is switched off when the power supply is not applied to the switch.

Abstract: A fan speed detection circuit includes a counter, an integrating circuit, a current regulation circuit, a connector and a matching circuit. The connector electrically connects to the current regulation circuit and a fan. The counter outputs a pulse signal, the integrating circuit receives the pulse signal from the counter, and converts the pulse signal from the counter into a corresponding analog command signal. The current regulation circuit adjusts the current from the integrating circuit according to the command signal and outputs the adjusted current to the connector. The matching circuit converts the voltage from the connector and provides a suitable voltage for activating the counter to enable the counter to detect and quantify and record the rotation speed of the fan in all circumstances.