Abstract: A speaker includes a shell and a vibration device. The vibration device is fixed on the shell. The shell defines a closed space. The closed space is filled with gas. The vibration device can drive the shell to vibrate to produce sound. A speaker is also provided.

Abstract: A speaker includes a shell and a vibration device. The vibration device is fixed on the shell. The shell defines a closed space. The closed space is filled with gas. The vibration device can drive the shell to vibrate to produce sound. A speaker is also provided.

Abstract: A system for modeling current transmission on a printed circuit board (PCB), the system includes a layout information obtaining module, a power setting module, a calculating module and an analyzing module. The layout information obtaining module obtains layout information of the PCB. The power setting module sets output voltages of multiple voltage regulating modules and a variation range of the output voltages. The calculating module builds a current transmission model script of the PCB according to the settings, executes the current transmission model script, and calculates working voltages of the multiple receiving terminals. The analyzing module compares the working voltages of the multiple receiving terminals with voltages of the variation range of the output voltages, and determines whether the layout information of the PCB complies with the design specification.

Abstract: A display device includes a top frame, a display, a printed circuit board, and a bottom frame. The top frame includes an anti-EMI cover panel and a securing portion extending from the anti-EMI cover panel. A receiving space is surrounded by the securing portion. The display is mounted in the top frame. The bottom frame includes a bottom panel and a mounting flange extending from the bottom panel. The printed circuit board is mounted on the bottom panel. The mounting flange is received in the receiving spaced and abuts an inner side of the securing portion. The anti-EMI cover panel, the securing portion, and the bottom frame cooperatively define an enclosed space for anti-EMI.

Abstract: An system for testing direct current (DC) layout of a printed circuit board, the system includes a layout information obtaining module, a rule loading module, a test script building module, a script executing module, and a report generating module. The layout information obtaining module obtains layout information of the printed circuit board. The rule loading module load DC transmission rules. The test script building module builds a DC transmission test scrip of the printed circuit board according to one of the DC transmission rules. The script executing module executes the DC transmission test script to determine whether the layout information of the printed circuit board complies with the one of the DC transmission rules. The report generating module generates a DC transmission testing report depicting whether the layout information of the printed circuit board complies with the one of the DC transmission rules and displays the testing report.

Abstract: A circuit board includes a signal plane and a ground plane. The signal plane is configured to have a plurality of signal traces. Each of the signal traces includes a plurality of straight line segments. Each line segment extends along a path different from the others. The ground plane includes a plurality of tiles connected in an array. Each tile is formed by ground traces. The straight line segments of each signal trace mapped on the ground plane are arranged at an angle relative to any one ground trace of the tiles. The angle is defined within a range determined by one of ground traces of a tile and an adjacent diagonal line of the tile. A method for laying out such a circuit board is also provided.

Abstract: A method for laying out a circuit board includes following steps. A substrate board is formed with a plurality of board sides. A ground plane, including a plurality of tiles, is provided. Each ground trace tile is defined by a plurality of ground traces. A signal plane on the substrate board has a plurality of signal traces that comprise of a plurality of straight line segments. Any one ground trace of each tile is arranged at an angle other than zero degrees relative to one determined board side. The straight line segments is applied to be mapped on the ground plane crossing one ground trace of one tile within an angle range determined by the ground traces of the tile and an adjacent diagonal line of the tile. The one ground trace and the straight line segments are applied at an angle movable in a range from 22.5° to 32.5°.

Abstract: A chip package structure including a carrier, a chip, and an underfill layer is disclosed. The carrier has a number of bumps disposed thereon. The chip has an active surface. The chip is flip-chip bonded and electrically connected to the carrier through the bumps such that the active surface of the chip faces the carrier. The underfill layer is disposed on the carrier between the chip and the carrier such that a gap is maintained between the underfill layer and the chip.

Abstract: A motherboard includes a printed circuit board, a first chip and a second chip arranged on the printed circuit board in parallel. A plurality of securing holes are defined in the printed circuit board around the first chip. At least one isolating hole is defined in the printed circuit board between the second chip and a first line determined by two of the securing holes close to the second chip. Should the printed circuit board suffer an impact, damage to the chips may be effectively minimized or prevented.

Abstract: A printed circuit board includes a base and a signal trace laid on the base. The signal trace includes a plurality of straight line segments parallel to the first fibers. The signal trace is laid on the base in such a manner that the line segments of the signal trace mapped on the base partly superpose the first fibers and partly superpose gaps between two adjacent first fibers.

Abstract: The invention related to a method and circuit that is used to compensate for S-parameters of a passive circuit which do not satisfy passivity. The method includes the following steps: (1) getting S-parameters which do not satisfy passivity, these S-parameters being composed of an S-parameter matrix S; (2) computing matrix [S×S?], wherein matrix S? is a complex conjugate transposed matrix of the S-parameter matrix S; (3) computing the eigenvalues of the matrix [S×S?], and choosing an eigenvalue ? whose real part real(?) is the biggest; (4) computing a compensating value ?, the compensating value ? being equal to real(?)1/2×(1+?), wherein the ? is a very small positive number; and (5) dividing each of the S-parameters by the compensating value ? to get the compensated S-parameters.

Abstract: A heat dissipating system includes a circuit board, a chip module, a first clamping member, a second clamping member, and a plurality of stress adjusting members. The circuit board includes a top surface and a bottom surface opposite to the top surface. The chip module includes a base portion located on the top surface of the circuit board via solder balls and a chip disposed on the base portion. The first clamping member abuts the chip. The second clamping member abuts the bottom surface of the circuit board. The stress adjusting members extend through the second clamping member and engage with the first clamping member.

Abstract: A circuit board assembly includes a circuit board having a first side and a second side opposite to the first side. A chip module is connected to the first side of the circuit board. The chip module includes a substrate and a chip disposed on the substrate. The first clamping member defines a recess and a contact portion around the recess. The chip is received in the recess, and the contact portion abuts the substrate. A second clamping member abuts the second side of the circuit board. A plurality of stress adjusting members extends through the second clamping member and engages the first clamping member.

Abstract: A circuit board assembly is provided, includes a circuit board having a first side and a second side opposite to the first side. A chip is connected to the first side of the circuit board. A first heat dissipating device is located on the first side of the circuit board. The chip is located between the first heat dissipating device and the first side of the circuit board. A second heat dissipating device abuts the second side of the circuit board, and the second heat dissipating device are secured to the first heat dissipating device to clamp the circuit board and the chip.

Abstract: A printed circuit board includes a base formed from a plurality of woven fibers, and signal traces laid on the base. Each of the signal traces includes at least a straight line segment. The signal traces are laid on the base in such a manner that the line segments of the signal traces mapped on the base cross the fibers at angles not equal to zero degrees.

Abstract: A heat dissipation apparatus for dissipating heat from two heat sources includes a heat sink, and a fan mounted on the heat sink. The heat sink includes a base and a plurality of parallel fins positioned on the base, the base contacts with one of the two heat sources for thermally conducting the heat generated by the one of the two heat sources. The fan is configured to generate airflow through the fins in such a manner that airflow flows from a second side of the fins to a first side of the fins. A deflecting member is mounted on the first side of the fins for deflecting airflow from the fan towards the second of the two heat sources.

Abstract: A circuit board assembly includes a circuit board with two heat dissipating assemblies mounted thereon and an L-shaped back plate attached to an underside of the circuit board. Each of the heat dissipating assembly includes at least a pair of securing members at opposite corners thereof. The back plate includes a first portion and a second portion each defining at least a pair of circular protrusions corresponding to the securing members of the heat dissipating assemblies.

Abstract: A computer enclosure includes a chassis with a plurality of heat generating components installed therein and an airflow guide structure. The airflow guide structure includes a fan and a duct attached to the fan. A pair of airflow outlets aligned with the fan is defined in the duct. The duct includes a plurality of pivot panels pivotally attached at airflow outlets. The pivot panels are configured to guide airflow from the fan to different positions of heat generating components in the chassis.

Abstract: A button assembly for pressing a switch in a computer bezel includes a button connected to an arm. A cutout is defined in the computer bezel. The button is inserted in the cutout, and the arm is pivotably mounted on the computer bezel. A pressing portion extends outward from a side of the arm. A slanted pressing plane is formed on the pressing portion. Pressing the button moves the arm so that one end of the slanted pressing plane away from the arm contacts the switch. The switch resists the pressing portion, causing the arm to rotate so that the other end of the slanted pressing plane moves forward, thereby the slanted pressing plane entirely contacts and activates the switch.

Abstract: An electronic apparatus includes an enclosure (30), a circuit board (40), a fan module (20), and an air guiding element (10) mounted in the enclosure. The circuit board includes at least one heat generating component (41) thereon. The fan module has a fan (22) and an output opening (213) corresponding to the fan. The air guiding element comprises a resisting panel (11) and a guiding panel (12) comprises a free end that extends toward the output opening of the fan module. The at least one heat generating component and the output opening are on the same side of the resisting panel. The guiding panel defines a free end (127) and a connecting end (125) connecting the resisting panel. A plane defined by the ends of the guiding panel is aligned at an angle larger than 90 degrees relative to the resisting panel.