Abstract: An electromagnetic generating device is used for testing an electromagnetic interference of electronic elements of an electronic device. The electromagnetic generating device includes a power source and a detector. The power source includes a power output. The detector includes a first magnetic guiding portion, a second guiding portion, and an electronic coil. The first magnetic guiding portion is connected to the second magnetic guiding portion. The electronic coil surrounds the second magnetic guiding portion. The electronic coil includes an input coupled to the power output of the power source, and an output being grounded.

Abstract: An electronic device includes a circuit board and a heat sink. A chip is mounted on the circuit board. The heat sink includes a base mounted on the chip and a number of heat-dissipation poles extending up from the base. Each pole defines a through hole extending through the base and a top end of the pole.

Abstract: A printed circuit board includes a first signal layer, a first ground layer, a second signal layer, a power layer, a second ground layer, and a third signal layer. The first signal layer includes an analog audio input/output (I/O) port and an audio chip. The audio chip includes a main body, a first group of signal pins connected to the analog audio I/O port, and a second group of signal pins connected to a control chip. The first ground layer, the power layer, and the second ground layer are each divided into an audio part and a digital part. The three audio parts act as a reference plane for traces between the analog audio I/O port and the audio chip, the three digital parts act as reference planes for traces between the control chip and the audio chip.

Abstract: A printed circuit board (PCB) includes a first wiring layer, a second wring layer, a power layer, a grounded layer, dielectric layers between every two active layers, a capacitor, and two through holes. A first portion of the power layer corresponding to the electromagnetic interference source is isolated from the power layer to form an independent power area. A first through hole connects the independent power area to an end of the capacitor, the second through hole connects a second portion of the power area to the other end of the capacitor. When the interference source produces interference, the interference is conducted to the independent power area and conducted to the second portion of the power area via the through holes and the capacitor.

Abstract: An electromagnetic generating device is used for testing an electromagnetic interference of electronic elements of an electronic device. The electromagnetic generating device includes a power source and a detector. The power source includes a power output. The detector includes a first magnetic guiding portion, a second guiding portion, and an electronic coil. The first magnetic guiding portion is connected to the second magnetic guiding portion. The electronic coil surrounds the second magnetic guiding portion. The electronic coil includes an input coupled to the power output of the power source, and an output being grounded.

Abstract: A printed circuit board includes a signal layer, a power layer, and a ground layer. The signal layer includes an analog audio input/output (I/O) port and an audio chip. The audio chip includes a main body, a first group of signal pins connected to the analog audio I/O port and a second group of signal pins connected to a control chip. The power layer and the ground layer each is divided into two unconnected parts, an audio part and a digital part, by a dividing groove. The two audio parts act as a whole reference plane for traces between the analog audio I/O port and the first group of signal pins of the audio chip. The two digital parts act as reference planes for traces between the control chip and the second group of signal pins of the audio chip.

Abstract: A printed circuit board includes a first signal layer, a first ground layer, a second signal layer, a power layer, a second ground layer, and a third signal layer. The first signal layer includes an analog audio input/output (I/O) port and an audio chip. The audio chip includes a main body, a first group of signal pins connected to the analog audio I/O port, and a second group of signal pins connected to a control chip. The first ground layer, the power layer, and the second ground layer are each divided into an audio part and a digital part. The three audio parts act as a reference plane for traces between the analog audio I/O port and the audio chip, the three digital parts act as reference planes for traces between the control chip and the audio chip.

Abstract: A printed circuit board includes a signal layer, a power layer, and a ground layer. The signal layer includes an analog audio input/output (I/O) port and an audio chip. The audio chip includes a main body, a first group of signal pins connected to the analog audio I/O port and a second group of signal pins connected to a control chip. The power layer and the ground layer each is divided into two unconnected parts, an audio part and a digital part, by a dividing groove. The two audio parts act as a whole reference plane for traces between the analog audio I/O port and the first group of signal pins of the audio chip. The two digital parts act as reference planes for traces between the control chip and the second group of signal pins of the audio chip.

Abstract: A low voltage differential signal (LVDS) cable includes a cable body, a power wire, a number of twisted lines for signal transmission, and a number of ground bare wires. The power wire is arranged in a center of the cable body. The number of twisted lines for signal transmission is equidistantly arranged around the power wire. Each signal transmission twisted line includes a pair of differential signal wires and a ground bare wire. The pair of differential signal wires and the ground bare wire are twisted together to form a triple-twisted line. The number of the ground bare wires is equidistantly arranged around the number of twisted lines for signal transmission.

Abstract: A low voltage differential signal (LVDS) cable includes a cable body, a power wire, a number of twisted lines for signal transmission, and a number of ground bare wires. The power wire is arranged in a center of the cable body. The number of twisted lines for signal transmission is equidistantly arranged around the power wire. Each signal transmission twisted line includes a pair of differential signal wires and a ground bare wire. The pair of differential signal wires and the ground bare wire are twisted together to form a triple-twisted line. The number of the ground bare wires is equidistantly arranged around the number of twisted lines for signal transmission.