P C B 可测性设计布线规则之建议― ― 从源头改善可测率PCB 设计除需考虑功能性与安全性等要求外，亦需考虑可生产与可测试。这里提供可测性设计建议供设计布线工程师参考。1. 每一个铜箔电路支点，至少需要一个可测试点。如无对应的测试点，将可导致与之相关的开短路不可检出，并且与之相连的零件会因无测试点而不可测。2. 双面治具会增加制作成本，且上针板的测试针定位准确度差。所以Layout 时应通过Via Hole 尽可能将测试点放置于同一面。这样就只要做单面治具即可。3. 测试选点优先级：A.测垫(Test Pad) B.通孔(Through Hole) C.零件脚(Component Lead) D.贯穿孔(Via Hole)(未Mask)。而对于零件脚，应以AI 零件脚及其它较细较短脚为优先，较粗或较长的引脚接触性误判多。4. PCB 厚度至少要62mil(1.35mm)，厚度少于此值之PCB 容易板弯变形，影响测点精准度，制作治具需特殊处理。5. 避免将测点置于SMT 之PAD 上，因SMT 零件会偏移，故不可靠，且易伤及零件。6. 避免使用过长零件脚(>170mil(4.3mm))或过大的孔(直径>1.5mm)为测点。7. 对于电池(Battery)最好预留Jumper，在ICT 测试时能有效隔离电池的影响。8. 定位孔要求：(a) 定位孔(Tooling Hole)直径最好为125mil(3.175mm)及其以上。(b) 每一片PCB 须有2 个定位孔和一个防呆孔(也可说成定位孔,用以预防将PCB反放而导致机器压破板)，且孔内不能沾锡。(c) 选择以对角线，距离最远之2 孔为定位孔。(d) 各定位孔(含防呆孔)不应设计成中心对称,即PCB 旋转180 度角后仍能放入PCB,这样,作业员易于反放而致机器压破板)9. 测试点要求：(e) 两测点或测点与预钻孔之中心距不得小于50mil(1.27mm)，否则有一测点无法植针。以大于100mil(2.54mm)为佳，其次是75mil(1.905mm)。(f) 测点应离其附近零件(位于同一面者)至少100mil，如为高于3mm 零件，则应至少间距120mil，方便治具制作。(g) 测点应平均分布于PCB 表面，避免局部密度过高，影响治具测试时测试针压力平衡。(h) 测点直径最好能不小于35mil(0.9mm)，如在上针板，则最好不小于40mil(1.00mm)，圆形、正方形均可。小于0.030”(30mil)之测点需额外加工，以导正目标。(i) 测点的Pad 及Via 不应有防焊漆(Solder Mask)。(j) 测点应离板边或折边至少100mil。(k) 锡点被实践证实是最好的测试探针接触点。因为锡的氧化物较轻且容易刺穿。以锡点作测试点，因接触不良导致误判的机会极少且可延长探针使用寿命。锡点尤其以PCB 光板制作时的喷锡点最佳。PCB 裸铜测点，高温后已氧化，且其硬度高，所以探针接触电阻变化而致测试误判率很高。如果裸铜测点在SMT 时加上锡膏再经回流焊固化为锡点，虽可大幅改善，但因助焊剂或吃锡不完全的缘故，仍会出现较多的接触误判。
上传时间： 2014-01-14
上传用户：cylnpy
We analyze, both analytically and numerically, the effectiveness of cloaking an infinite cylinder from observations by electromagnetic waves in three dimensions. We show that, as truncated approximations of the ideal permittivity and permeability tensors tend towards the singular ideal cloaking fields, so that the anisotropy ratio tends to infinity, the D and B fields blow up near the cloaking surface. Since the metamaterials used to implement cloaking are based on effective medium theory, the resulting large variation in D and B will pose a challenge to the suitability of the field averaged characterization of " and 碌. We also consider cloaking with and without the SHS (softand- hard surface) lining, shown in [6] to be theoretically necessary for cloaking in the cylindrical geometry. We demonstrate numerically that cloaking is significantly improved by the SHS lining, with both the far field of the scattered wave significantly reduced and the blow up of D and B prevented.
标签： effectiveness analytically numerically cloaking
上传时间： 2017-03-30
上传用户：zxc23456789
As I write this foreword, I am collaborating with four leading user interface (UI) component vendors on a presentation for the 2004 JavaOneSM conference. In our presentation, the vendors will show how they leverage JavaServerTM Faces technology in their products. While developing the presentation, I am learning some things about the work we’ve been doing on JavaServer Faces for the past three years. The vendors have their own set of concerns unique to adapting their product for JavaServer Faces, but they all voice one opinion loud and clear: they are very relieved to finally have a standard for web-based user interfaces.
标签： collaborating component interface foreword
上传时间： 2014-08-27
上传用户：时代电子小智
Abstract-In this paper, simple autonomous chaotic circuits coupled by resistors are investigated. By carrying out computer calculations and circuit experiments, irregular self-switching phenomenon of three spatial patterns characterized by the phase states of quasi-synchronization of chaos can be observed from only four simple chaotic circuits. This is the same phenomenon as chaotic wandering of spatial patterns observed very often from systems with a large number of degrees of freedom. Namely, one of spatial-temporal chaos observed from systems of large size can be also generated in the proposed system consisting of only four chaotic circuits. A six subcircuits case and a coupled chaotic circuits networks are also studied, and such systems are confirmed to produce more complicated spatio-temporal phenomena.
标签： investigated Abstract-In autonomous resistors
上传时间： 2014-06-09
上传用户：h886166
AC220V转DC(12V15W )电源板AD设计硬件原理图+PCB文件，2层板设计，大小为100*55mm, ALTIUM设计的原理图+PCB文件，可以做为你的学习设计参考。主要器件型号如下：Library Component Count : 24Name Description----------------------------------------------------------------------------------------------------2N3904 NPN General Purpose Amplifier2N3906 PNP General Purpose AmplifierBRIDGE1 Diode BridgeCON2 ConnectorCap CapacitorCap Pol1 Polarized Capacitor (Radial)D Zener Zener DiodeDIODE Diode 1N914 High Conductance Fast DiodeECELECTRO2 Electrolytic CapacitorFP103 FUSE-HHeader 2 Header, 2-PinINDUCTOR2 NMOS-2 N-Channel Power MOSFETPC837 OptoisolatorRES2-B Res Varistor Varistor (Voltage-Sensitive Resistor)T TR-2B TRANS1UCC28051 Volt Reg Voltage Regulator
上传时间： 2021-11-21
上传用户：kent
DHT11 MIC SHT11 VS1838B CHT8305 MQ-3 温湿度气体等传感器元件Altium封装库三维视图PCB封装库(3D封装库),PcbLibb后缀文件，封装列表如下：Component Count : 32Component Name-----------------------------------------------AHT10CHT8305DHT11DHT11 - duplicateGP1A52HRGP1A53HRI-LED-3MMI-LED-5MMMIC-4.5*1.9MIC-6*5.5mmMIC0622DIPMLX90614MQ-3MS5611OPT-3MMOPT-5MMRG5528ROC16S58SHT1X-8PSHT2XSHT3x-ARPSHT3x-DISST188TO-18TO-39TO-66TO-356VS1838B-AVS1838B-A_HVS1838B-BVS1838B-B_H
上传时间： 2021-12-21
上传用户：shjgzh
基于DSP设计的数字化大功率电源数字化全桥变换器电源ALTIUM设计硬件原理图+PCB文件，包括主板和控制板2个硬件，均为4层板设计，ALTIUM设计的硬件工程文件，包括完整的原理图和PCB文件，可以做为你的设计参考。主板原理图器件如下：Library Component Count : 55Name Description----------------------------------------------------------------------------------------------------6CWQ09F Schottky Rectifier7416474HC16474LS1647805 7812 7815 7824 ACT45B 共模电感ARRESTER R27030059BAV99 R26010005BRIDGE R26060153CAPCB CD CON4 ConnectorComponent_1_1 D-1N5819 DiodeDEDIO-SMDELECTRO1 R21010742FUSE R27010205HOLHeader 3 Header, 3-PinHeader 6 Header, 6-PinHeader 7 Header, 7-PinIR1150S JQX-115F-I L0 L2 LBAV70 R26010012LM358MOSFET N NMOS-2 R26110100NPN R26080003OPTOISO1 R25030015PNP PNP TransistorR-NTCR20190006 R20190075R21020037 R21020037/工业B/消费C/瓷片电容/4700pF±20%/250Vac/Y2/Y5U/引脚间距7.5mmR26020054 R26020054/工业A/消费C/快恢复二极管/1000V/1A/1.7V/75ns/SMA/US1M-E3-61TR26030048 R26030048/工业A/消费B/肖特基二极管/1A/100V/0.79V/SMA/SS110LR26030097 R26030097/工业B/肖特基二极管/60V/1A/0.70V/SMA/B160R29030691 R29030691/防雷接地座/最大尺寸7.36*7*10/紫铜镀锡RES R20190099RES2 RES_1Res3 ResistorTL431 TRANS01TRANS7-9 Transformer UCC3804VARISTOR R27030060ZENERu型槽3.5x7
标签： tms320f28035 dsp 全桥变换器
上传时间： 2021-12-22
上传用户：aben
LED灯封装Altium Designer AD PCB封装库2D3D元件库文件PCB Library : LED.PcbLibDate : 2020/12/29Time : 16:50:29Component Count : 49Component Name-----------------------------------------------LED 1W/3WLED 1W/3W-WLED 3mm-2PLED 3MM-BLED 3MM-GLED 3MM-RLED 3MM-WLED 3MM-YLED 3MM-YCLED 5MM-BLED 5MM-GLED 5MM-RLED 5MM-WLED 5MM-YLED 5MM-YCLED 0603-RGLED 0603BLED 0603GLED 0603RLED 0603WLED 0603YLED 0805BLED 0805GLED 0805RLED 0805WLED 0805YLED 1206BLED 1206GLED 1206RLED 1206WLED 1206YLED 3528-2PinLED 3528-4PinLED 5050LED 5630LED 5730-VLED F234-BLED F234-GLED F234-RLED F234-WLED F234-YLED F257-BLED F257-GLED F257-RLED F257-WLED F257-YLED SH-5MM-WLED SH-8MMLED SH-8MM-W
标签： led 封装 altium designer pcb
上传时间： 2022-03-11
上传用户：
电位器封装Altium Designer AD PCB封装库2D3D元件库文件PCB Library : 电位器.PcbLibDate : 2020/12/29Time : 14:48:56Component Count : 38Component Name-----------------------------------------------3006P3266W3266X3266Y3266Z3296W3303W3306W3319P3362P3386P3386WCLK_VOLUMEEC11EC11-BFADER75-6PTR902-L15RK0971221-L15RK0971221-L20RM065RV097-1-G15RV097-2-G15RV097-K-1-G15WH148-1-G15WH148-1-G18WH148-1-G20WH148-1-G25WH148-2-G15WH148-2-G18WH148-2-G20WH148-2-G25WH148C-2-G15WH148C-2-G18WH148C-2-G20WH148C-2-G25XV09223NPV-20FXV09223NPV-25FXV09223NPV-30F
标签： 电位器 封装 altium designer
上传时间： 2022-03-12
上传用户：wangshoupeng199
晶振晶振封装Altium Designer AD PCB封装库2D3D元件库文件PCB Library : 晶振.PcbLibDate : 2020/12/29Time : 14:42:25Component Count : 38Component Name-----------------------------------------------OSC 455E-LIOSC 455E-WIOSC 1612-4POSC 2025-4POSC 3215-2POSC 3225-4POSC 4025-4POSC 5032-2POSC 5032-4POSC 6035-2POSC 6035-4POSC 7050-2POSC 7050-4POSC 8045-2POSC 8045-4POSC 8045-4P-COSC HC-49SOSC HC-49SMDOSC HC-49UOSC MC-146OSC MC-156OSC MC-306OSC MC-405OSC MC-406OSC UM-1OSC UM-5OSC-2x6-LIOSC-2x6-WI-AOSC-2x6-WI-BOSC-2x6-WSOSC-3x8-LIOSC-3x8-WI-AOSC-3x8-WI-BOSC-3x8-WSOSC-3x10-LIOSC-3x10-WI-AOSC-3x10-WI-BOSC-3x10-WS
标签： 封装 altium designer
上传时间： 2022-03-12
上传用户：
