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: A Universal Serial Bus (USB) hub includes a USB input, a number of USB outputs, a USB controller, a power processing module, and an alarm. The USB controller controls data transmission between a connected USB device connected to the USB output and a computer. The power processing module obtains a power of each USB output and sums the power of all the USB outputs. The power processing module further compares a preset power value with the sum of the power. When the sum of the power is greater than the preset power value, the power processing module outputs a control signal to activate the alarm.

Abstract: An audio test cable includes three types of audio input and output (I/O) ports. The input port and the output port in each type of audio I/O ports form a short circuit for carrying a loopback test for a motherboard. The audio test cable also includes a test audio jack which connects to the output port of all types of audio I/O ports for carrying out an audio-quality test for the motherboard.

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 socket protection device includes a fixing member, a cover, a limiting member, and an operation member. The fixing member is secured to a circuit board. The fixing member includes a pair of first connecting blocks. The cover includes a second connecting block, a first latching portion, and a second latching portion. The limiting member is secured to the circuit board. The operation member includes a shaft and an operation rod secured to the shaft. The shaft rotatably connects the cover to the fixing member via the first and second connecting blocks. When the operation rod is pressed to drive the shaft to rotate, the cover is rotated toward the socket. When the cover covers the socket, the first latching portion latches the limiting member, and the second latching portion latches the operation rod.

Abstract: An exemplary motor control circuit for controlling a motor includes a motor driving chip, a sensing unit, and a controller. The motor driving chip motor driving chip is electronically connected to the motor. The sensing unit includes a proximity sensor, the proximity sensor detects whether an external object is proximate to the proximity sensor. The controller is electronically connected to the motor driving chip and the sensing unit, the controller controls the motor driving chip to drive the motor to rotate in a first direction when an external object is detected, and controls the motor driving chip to drive the motor to rotate in a second direction reverse to the first direction when no external object is detected for a predetermined period of time.

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.

Abstract: A power supply system for an air conditioner of a car includes a battery, an alternator, a detection circuit to detect whether the alternator is operating and outputting a detection signal according to the detection result, a processing unit to output a control signal according to the detection signal, and a switching circuit to connect either the battery or the alternator to the air conditioner.

Abstract: A circuit for clearing complementary metal oxide semiconductor (CMOS) information of a CMOS chip includes a battery, first to fifth resistors, first and second electronic switches, a switching unit, and first and second diodes. The circuit can clear information of the CMOS chip when one or more switches are activated.

Abstract: An audio test cable includes three types of audio input and output (I/O) ports. The input port and the output port in each type of audio I/O ports form a short circuit for carrying a loopback test for a motherboard. The audio test cable also includes a test audio jack which connects to the output port of all types of audio I/O ports for carrying out an audio-quality test for the motherboard.

Abstract: A reception apparatus for flexible cable modules includes a plurality of holding units. Each of the holding units includes two holding bars and a holding board. The two holding bars are parallel to each other, and the two holding bars of each of the holding units are rotatably assembled with the two holding bars of a next one of the holding units to rotatably assemble all of the holding units one by one and form assemble apertures between adjacent ones of the holding board. The flexible cable modules repeatedly pass through selected ones of the assembling apertures to be held on the reception apparatus.

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 test device for testing a printed circuit board (PCB) includes a base and a measuring device. The measuring device includes a testing pin and is capable of measuring any desired point of the PCB on condition that the pin makes contact with the point at an included angle between the pin and a back surface of the PCB which is larger than a predetermined angle. The distance between the base and the PCB satisfies: H>L tan ?, where H is the vertical distance between the PCB and the base, L is the maximum length of an orthogonal projection of the pin on the PCB when the pin is contacting the point, and ? is the predetermined angle.

Abstract: A resistance measuring circuit for measuring a resistor includes an amplifier, a transistor, a variable resistor, a first resistor, and a second resistor. The transistor includes a base connected to the output of the amplifier, a collector connected to a direct current (DC) power supply, and an emitter. The first resistor includes a first terminal connected to the DC power source, and a second terminal grounded through the variable resistor and connected to the non-inverting terminal of the amplifier. The second resistor includes a first terminal connected to the inverting terminal of the amplifier and connected to the emitter of the transistor through the resistor to be measured, and a second terminal grounded.

Abstract: A fan module includes a fan, a bracket, a number of first fasteners, and a number of second fasteners. The bracket includes a base wall defining a number of locking holes. The fan includes a side plate defining a number of mounting holes. Each of the first fasteners includes a pole, a head portion, and a locking portion. A through hole is defined in the first fastener. A block protrudes on an inner surface of the through hole of the first fastener, aligning with the locking portion. Each of the second fasteners includes a shaft. The pole extends through the locking hole and the mounting hole of the fan. The shaft extends through the through hole of the first fastener to engage with the block, to deform the locking portion. Therefore the locking portion is locked to an inner surface of the side plate of the fan.

Abstract: A test circuit includes two probes, a comparison circuit, a switch circuit, and an indication circuit. The probes are connected to an electronic component to be tested, and a low level signal is output if the electronic component is short-circuited. The comparison circuit outputs a comparison signal based on the shorting signal from the probes. The switch circuit outputs a switch signal based on the comparison signal from the comparison circuit. The indication circuit indicates that the electronic component is short-circuited or not short-circuited based on the switch signal fro m the switch circuit.

Abstract: An electronic locking assembly includes an electronic lock and an electronic key for unlocking the electronic lock. The electronic key includes a first memory for storing a first password, and a first signal transceiver for encoding the first password into a first wireless signal and transmitting the first wireless signal. The electronic lock includes a main body for physically locking or unlocking the device, a second memory for storing a second password, a second signal transceiver, a processor, and a comparator. The second signal transceiver receives the first wireless signal and decodes the first wireless signal into the first password. The processor sends the first password and the second password to the comparator. The comparator compares whether the first password second password match, and thus to control the main body to physically lock or unlock the device.