Abstract: A power supply circuit preventing any overvoltage to an electronic element includes a voltage conversion unit and a voltage clamping unit. The voltage conversion unit converts voltage of a power supply into an operation voltage of the electronic element, and outputs the converted voltage through an output terminal of the voltage conversion unit. When the voltage output from the output terminal of the voltage conversion unit is more than the operation voltage of the electronic element, the voltage clamping unit effectively clamps the voltage output from the output terminal of the voltage conversion unit down to the operation voltage of the electronic element.

Abstract: A discharge circuit includes a pulse width modulator (PWM) chip, a first and second electronic switch, and a resistor. The first electronic switch receives a voltage creep from the PWM chip. When the voltage creep is less than a voltage making the first electronic switch to turned on, the voltage creep is discharged through the resistor and the second electronic switch.

Abstract: A mounting apparatus for an expansion card includes a fixing bracket receiving the expansion card, and a supporting member mounted to the fixing bracket. The fixing bracket includes an end plate fixing a rear end of the expansion card. The supporting member includes a support wall substantially parallel to the end plate of the fixing bracket. The support wall includes a holding portion to retain a front end of the expansion card. The supporting member is slidable to render the distance between the supporting member and the end plate of the fixing bracket substantially equal to the lengths of various expansion cards.

Abstract: A mounting device for fixing an optical disk drive (ODD) includes a latch and a rack including a bottom wall. Two pins extend out from opposite sides of the ODD. A first plate and a second plate extend up from the bottom wall to sandwich the ODD. a tab extends inward from a back end of one of the first and second plates to block a back end of the ODD. An opening and a slot below and communicating with the opening are defined in each of the first and second plates. The latch is pivotally mounted to the first plate adjacent to the slot. The pins of the ODD extend into the slots through the corresponding openings. One of the pins is blocked by the latch.

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 fixing device for use with at least one expansion card in a computer chassis includes a positioning member and a fixing member. One side of the positioning member defines at least one first slot. The fixing member includes a fixing portion and a rotatable portion rotatablely connected to the fixing portion. The fixing portion defines at least one second slot corresponding to the at least one first slot. When the rotatable portion is able to rotate to a position where the at least one first slot face to the at least one second slot, allowing opposite sides of the free end of the at least one expansion card.

Abstract: An electronic device includes an enclosure and a detachable module. The enclosure includes a positioning wall and a positioning pin protruding in from a first end of the positioning wall. The detachable module includes a side plate parallel to the positioning wall, a latching member rotatably mounted to the side plate, and a resilient member fixed to the latching member to resiliently abut the side plate. A latching block extends down from a distal end of the latching member. The latching block includes a guiding surface on a bottom of the latching block and an engaging surface. The detachable module is inserted into the enclosure from a second end of the positioning wall. The guiding surface slides along the positioning pin, to allow the latching member to rotate, deforming the resilient member, until the engaging surface abuts the positioning pin.

Abstract: An anode of a light emitting diode (LED) and a second terminal of a third electrical switch are connected to a first power source. First terminals of the first and second electrical switches are respectively connected to a second power source and a suspend signal pin. A second terminal of the first electrical switch is connected to a cathode of the LED and an output pin of a counter chip. A second terminal of a second electrical switch is connected to the first power source through a first resistor and a first terminal of the third electrical switch. A third terminal of the third electrical switch is grounded through second and third resistors and a capacitor in sequence and a voltage pin of the counter chip.

Abstract: A keyboard for an electronic device includes a main body, a test indicator positioned on an outside surface of the main body, and an interface electrically connected to both the main body and the test indicator. Both the main body and the test indicator are electrically connected to a main board of an electronic device through the interface. The electronic device can be operated using the keyboard, and the test indicator indicates the working status of the electronic device.

Abstract: A voltage-stabilizing circuit for stabilizing an output voltage of a power integrated circuit (IC) includes an electronic switch and an RC circuit. The RC circuit includes a resistor and a capacitor. A first terminal of the resistor receives an enable signal and is connected to a control terminal of the electronic switch. A second terminal of the resistor is grounded through the capacitor, and is further connected to an enable pin of the power IC. A first terminal of the electronic switch is connected to a node between the resistor and the capacitor. A second terminal of the electronic switch is grounded.

Abstract: The circuit board includes a main body, at least one handle, and at least one connecting element. The main body defines at least one through hole. One end of each of the at least one handle defines a positioning portion. The positioning portion of each of the at least one handle extends through a corresponding one of the at least one through hole and is engaged with one of the at least one connecting elements.

Abstract: A mouse includes a casing, a light, a switch, and a supporting device. The casing includes a base plate and a top cover covering the base plate. The top cover defines a receiving hole. The switch is electrically connected to the light and used to turn the light on and off. The supporting device is movably accommodated in the receiving hole and supports the light. The supporting device is capable of moving out of the receiving hole.

Abstract: A desktop computer includes a host portion, a network interface card and a first interface. The network interface card includes a first pin, a second pin, and a third pin. The first interface includes a fourth pin connected to both the second and third pins of the network interface card, and a fifth pin connected to the first pin. The screen includes a second interface connected to the first interface, a first LED, and a second LED. The second interface includes a sixth pin connected to the fourth pin, and a seventh pin connected to the fifth pin. The seventh pin is connected to a power supply through the first LED. The sixth pin is connected to the power supply through the second LED. When there is communication through a network connection, the first LED and the fourth LED to flash synchronously.

Abstract: A chassis of an electronic device includes an enclosure and a number of ball bars each having a number of balls. The enclosure defines a number of through holes. The ball bars are installed to an inner surface of the enclosure so the balls are rotatably received in the through holes. A lower part of each ball extends out of a bottom surface of the enclosure through the through hole.

Abstract: A mounting apparatus for mounting a hard disk drive backplane to a side of a bracket in a chassis includes a first mounting member, a second mounting member, a pivot member, and a locking member. The bottom and opposite ends of the backplane are clipped to the bracket. The second mounting member is fixed to a top side of the backplane and is locked to a top plate of the bracket. The first mounting member is fixed to a bottom side of the backplane. The first mounting member includes an engaging portion. The locking portion is fixed to the chassis. A first end of the pivot member is pivotably mounted to the chassis. A second end of the pivot member is locked to the locking member. A pressing portion extends down from a middle of the pivot member to press the engaging portion on the chassis.

Abstract: A keyboard includes a fingerprint input unit, a storage unit, a switch unit, and a control unit. The fingerprint input unit receives fingerprint information of a user. The storage unit stores a fingerprint model. The control unit is connected to the fingerprint input unit, the storage unit, and the switch unit. The control unit receives the fingerprint information of the user from the fingerprint input unit and compares the received fingerprint information with the fingerprint model stored in the storage unit. If the received fingerprint information is consistent with the fingerprint model, the control unit controls the switch unit to be turned on, to output a control signal to power on a computer connected to the keyboard.

Abstract: A device includes a light emitting diode (LED) module and a switch. The switch further includes a first contact grounded through a first resistor, a second contact grounded through a second resistor, and a fixed contact connecting to the LED module. When the fixed contact is connected to the first contact and the first resistor, the device is operated as a display device and the LED module is operated as a backlight source for the display device. When the fixed contact is connected to the second contact and the second resistor, the LED module is operated as a light source.

Abstract: A computer chassis includes a chassis body, a control unit, a motor unit, a gate unit and a detection unit. The chassis body defines an opening. The motor unit is electronically connected to the control unit. The gate unit is connected to the motor unit. The detection unit is electronically connected to the control unit. The gate unit and the detection unit are positioned in the opening, the detection unit detects and sends a detection signal to the control unit, the control unit receives the detection signal and control the motor unit to closes the gate unit.

Abstract: A fixing device includes a support fixed in a chassis, and a bracket installing a fan. The support includes a mounting plate. The mounting plate defines a vent area and a number of latching holes located around the vent area. The bracket includes a number of pins respectively latched into the latching holes of the support and a positioning portion. A tab protrudes from the support, to engage with the positioning portion of the bracket. An elastic portion extends down from the bracket to resiliently abut against the chassis.

Abstract: A holding frame includes a holder body, a printed circuit board, a rotatable cover, and a subsidiary hard disk drive assembly. The rotatable cover is rotatably connected to the holder body. The subsidiary hard disk drive assembly is slidably attached to the rotatable cover, and faces the printed circuit board.