摘要:
A method of testing a printed circuit board (PCB) acquires test points from a wiring diagram of the PCB. Frequency domain tested items for each test point and a standard value of each frequency domain tested item are preset. A distance between a preset fiducial point and each test point is computed to create a testing order of the test points according to the distances. The frequency domain tested items of each test point are computed according to the testing order. A pass or a failure of each test point is displayed according to a determination of if each of the computed frequency domain tested items within the corresponding standard value, and a test result of the PCB is output according to the passes or the failures.
摘要:
A computer determines a first origin of a first coordinate system of a PCB, and controls a robotic arm to position a probe above the first origin. Furthermore, the computer determines a second origin of a second coordinate system of the robotic arm, and determines displacement values from the first origin to a test point in controlling movements of the robotic arm in the second coordinate system. A graph representing the test point is recognized in an image of the PCB, pixel value differences between the graph center and the image center are determined and converted to displacement correction values for controlling the movements of the robotic arm and determining 3D coordinates of the test point. The robotic arm is moved along a Z-axis of the second coordinate system to precisely position the probe on the test point of the PCB.
摘要:
A printed circuit board (PCB) includes two layers, two signal transmission traces, and a vertical interconnect access (via). The signal transmission traces are respectively arranged on the layers. The signal transmission traces are electrically connected to each other through the via. A centerline of the via with a vertical line of the layers form an acute angle θ, the angle θ is less than cos−1[(Lv2−Lt2)/(Lv2+Lt2)]. Wherein Lt is loss of the two signal transmitting traces in a unit length, and Lv is loss of the via in a unit length.
摘要:
A clamping mechanism for holding a workpiece includes an end executor, a driving member, and a contact member detachably mounted on the end executor. The end executor includes a plurality of claws arranged in matrix. The contact member includes a mounting board and a plurality of contact sleeves corresponding to the claws. The driving member is capable of driving the mounting board, moving the contact sleeves to extend the claws, and hold the workpiece.
摘要:
A computer motherboard includes a printed circuit board which includes a central processing unit (CPU) socket and a group of memory slots. The group of memory slots includes an in-line type memory slot and a surface mounted device (SMD) type memory slot. The in-line type memory slot includes a number of plated through holes. The SMD type memory slot is set between the in-line type memory slot and the CPU socket. The through holes of the in-line type memory slot are connected to the CPU socket through traces, pads of the SMD type memory slot are connected to corresponding through holes of the in-line type memory slot having the same pin definition.
摘要:
The REVERSING TRANSMISSION includes a shaft, a retainer, a spacing collar, a plurality of reversing members, two gears and two covers. The holder is sleeved on the shaft with spaced sliding notches formed thereon. The spacing collar is mounted on an outer surface of the retainer. The reversing members each includes two spaced swing plates with two reversed spiral teeth dented on two diagonal half surfaces of the two spaced swing plate. The reversing members slide into the sliding notches of the holder with two swing plates distributed at different side of the spacing collar. Each of the gears has a group of spiral teeth formed on the inner side for engaging with the group of spiral teeth of the reversing members, and cogs formed on the outer circumference surface. The covers are mounted on two opposite ends of the holder to keep the reversing member in position.
摘要:
Parameters of a radio frequency filter can be changed by changing structure of each component of the filter. Material of each component, diameters of each of magnetic cylinders, density of each of conductive coils, thickness of a dielectric layer, and thickness of an insulation tube can be changed. When any component needs to be replaced, each cover is rotated, with connection partitions moving to two slots of an insulation portion, to detach the filter.
摘要:
An apparatus for adjusting a differential probe includes a regulator arranged therein capable of adjusting a distance between two tips of the probe. The probe is supported on the apparatus. The apparatus includes a rotatable shaft and a rotatable disk. The rotatable shaft engages with the regulator of the probe. The rotatable disk is mounted surrounding the rotatable shaft and rotatable together with the rotatable shaft. An angular ruler or a radian ruler is described on an outer surface of the rotatable disk to indicate a rotation angle or a rotation radian of the rotatable shaft, therefore the distance between the two tips of the probe are accurately adjusted.
摘要:
A method calibrates a second oscilloscope according to setting values of a first oscilloscope. The setting value of the first oscilloscope is stored into a first file which is readable by any oscilloscope, and also into a second file. Test data obtained from testing an electronic signal using the first oscilloscope is stored into a third file, and waveform data obtained from testing the electronic signal are stored into a fourth file. The second oscilloscope acquires the first file, the second file, the third file, and the fourth file to reset the setting value of the second oscilloscope to the same as the setting value of the first value, for reproducing the test data of the third file and the waveform data of the fourth file.
摘要:
A clamp apparatus includes a mounting base, a rotation actuator mounted to the mounting base, a beveled active gear driven by the rotation actuator, and at least two clamp jaws rotatably connected to the mounting base. Each clamp jaw includes a beveled driven gear engaging the beveled active gear of the clamp apparatus and a clamp body connected to the beveled driven gear. When the clamp jaws are rotated together with the beveled driven gear, the clamp bodies are moved toward or away from each other to clamp or release a workpiece, respectively.