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As a new member of switching power supply family, currently, LED switching power supply has been applied widely in many fields. In the R&D of new products, layout of PCB components is the most important part in designing LED switching power and a key test for engineers in designing the schemes as well. Then, what should we do achieve the best effects in the layout of PCB components? To achieve the best OCB components layout for the LED switching power supply, the first point which deserves full attention is the size of PCB before designing the layout of PCB components. When the size of PCB is too large, the printing wires will have to bee very long, leading to an increase in the impedance and a reduction in noise immunity, as well as a rising cost. In addition, once the printing wires are too long, neighbouring wires will be easily disturbed. Generally, the best shape for a PCB universal for the LED switching power is rectangle, with a proportion of 3:2 or 4:3 in length and width

As an important electronic connector, PCB is almost widely applied in all the electronics, which is considered as “the mother of the electronics”. Therefore, technological transformation and market research of the PCB industry has become the focus of many insiders. There are two obvious trends in the present electronic products: one is being light and short while the other is being high-speed and high-frequency, which drives the downstream PCB to develop into a high-density, high-concentration, encapsulating, sophisticated and multi-layer ones and contributes to a rising demand for high-layer plates and HDI. Being short in length of wiring and with low circuit impedance, high-layer plates, with the advantages of work with high frequency, stable performance, however, have more complicated functions, which is an unavoidable trend for the electronics technology to develop into a high –frequency, high-speed, multi-function, high-capacity ones. Besides, the further application of lar

The news that the output value of China’s PCB industry will rise to the first place across the globe in the next two years shocks the 

但是由于市场价格竞争激烈， PCB板 材料成本也处于不断上升的趋势，越来越多厂家为了提升核心竞争力，以低价来垄断市场。然而这些超低价的背后，是降低材料成本和工艺制作成本来获得，但器件通常容易出现裂痕(裂缝)、易划伤、(或擦伤)，其精密度、性能等综合因素并未达标，严重影响到使用在产品上的可焊性和可靠性等等。 面对市面上五花八门的PCB线路板，辨别PCB线路板好坏可以从两个方面入手;第一种方法就是从外观来分判断，另一方面就是从PCB板本身质量规范要求来判断。 ▼判断PCB电路板的好坏的方法： 第一：从外观上分辨出电路板的好坏 一般情况下，PCB线路板外观可通过三个方面来分析判断; 1、大小和厚度的标准规则。 线路板对标准电路板的厚度是不同的大小，客户可以测量检查根据自己产品的厚度及规格。 2、光和颜色。 外部电路板都有油墨覆盖，线路板能起到绝缘的作用，如果板的颜色不亮，少点墨，保温板本身是不好的。 3、焊缝外观。 线路板由于零件较多，如果焊接不好，零件易脱落的线路板，严重影响电路板的焊接质量，外观好，仔细辨认，界面强一点是非常重要的。 第二：优质的PCB线路板需要符合以下几点要求 1、要求元件安装上去以后电话机要好用，即电气连接要符合要求; 2、线路的线宽、线厚、线距符合要求，以免线路发热、断路、和短路; 3、受高温铜皮不容易脱落; 4、铜表面不容易氧化，影响安装速度，氧化后用不久就坏了; 5、没有额外的电磁辐射; 6、外形没有变形，以免安装后外壳变形，螺丝孔错位。现在都是机械化安装，线路板的孔位和线路与设计的变形误差应该在允许的范围之内; 7、而高温、高湿及耐特殊环境也应该在考虑的范围内; 8、表面的力学性能要符合安装要求; 以上就是PCB线路板判断好坏的方法，在选购PCB线路板的时候，一定要擦亮眼睛。

早期准备 - PCB结构设计 - PCB 布局 - 配线 - 配线优化和丝网 - 网络和DRC检查和结构检查 - 原型生产。 I：早期准备包括准备组件库和原理图 PCB元件库要求很高，直接影响电路板的安装，只要基极引脚和PCB元件的特性协调良好，对SCH元件库的要求就很低。 PS：应该更加注意标准库中隐藏的基础引脚。 下一步是原理图的设计，之后将开始PCB设计。 二：PCB结构设计 在此步骤中，根据确定的电路尺寸和机械定位，可以在PCB的设计条件下绘制PCB布局，并且连接器，按钮/开关，螺孔，导孔等组件应相应放置在正确的位置。全面关注布线区域和非布线区域（螺钉孔周围的大部分区域都是非布线区域。） III。 PCB布局 简单地说，布局实际上是指在电路板中放置元件。 如果上面提到的所有准备工作都做得很好，可以在原理图中自动创建设计 - 创建列表，然后将Design-LoadNets导入到 PCB在线 图中，然后看到组件堆叠在板上自动与底座引脚中的飞线指示连接。 接下来，可以布置组件，这需要很大的努力，因为该步骤确定了板的整体图像和下一个路由的复杂程度。 在布局过程中，可以在实际路由之前尝试初始路由，当不确定时，应该充分注意。     IV。 路由 布线是整个PCB设计中最重要的程序，它可以直接决定PCB板的性能。 在PCB设计过程中，路由一般可分为三个层次：第一层是路由连接，这是设计PCB的基本要求。 如果路线与全线飞线没有很好地连接，则可以将该板称为不合格的，或者不通过。 第二级是满足电器的需求。 五，路由的主要原则 通常，第一步是布置电线和接地电极以确保电路板的电气性能。 如果可能，尝试在一定限度内加宽电线和接地电极的宽度。 接地电极比电线宽，宽度关系如下：接地电极>电线>信号线。 一般信号线宽度为0.2 ~ 0.3m，最小宽度为0.05 ~ 0.07mm ， 电线宽度一般为1.2 ~ 2.5mm。 用于数字电路的PCB可以通过采用宽接地导线形成回路，即用人工电路构建接地屏（不能应用于地）。

The hot August has witnessed an extraordinary boom in the PCB market of China. With half a year gone, there is appearing a wave in the PCB industry to show their own performance report. According to The Sixteenth Ranking List of the  PCB industry  released by CPCA which can be called a list of weight, among which 137 PCB enterprises, 12 copper-clad enterprises, 15 material for special use enterprises, 9 special chemicals enterprises, 9 facility and instrument enterprises for PCB special use and 4 environmental protection and cleaning enterprises were enlisted with an honor of enterprise with over RMB 1000 million. As You Li, the president of CPCA, said, the year 2016 was a year full of challenges as well as pains for the manufacturing industry in China. Faced with the complex and varied economic conditions, people in the PCB industry fought their way and made great achievements. The total business revenue of the PCB industry in the list amounts to RMB 164.216 billion, an increase