On the Printed circuit boards(PCB)

Aug 21 , 2020

On the Printed circuit boards(PCB)

A printed circuit board is a panel or plate made up of one or a pair of conductive patterns. They are located on the surface of the dielectric base. In some cases, a system of conducting patterns located on the surface and in the volume of the dielectric base is used. The main purpose of printed circuit boards is to mechanically fasten quantum electronics and electronic technology, as well as to connect them electrically.

Varieties of printed circuit boards

The simplest option is a plate with copper conductors on one side, connecting the elements of the conductive pattern only on its surface. Such products are known as single layer printed circuit boards (PCBs).

One of the most popular options is dual-layer boards (DPP), which contain two layers (the conductive pattern is located on both sides of the product). Through transition and mounting metallized holes are provided to connect conductors. Depending on the complexity of the design, for example, if the wiring becomes too complex, multilayer printed circuit boards (MPP) are ordered from the factory. They are made of alternating layers of insulating material, while the conductive patterns are on two or more signal layers, between which the necessary connections are made. To ensure electrical connection between them, holes with electro-galvanic metallization are used.

Key benefits of multilayer PCBs:

  • variability in the number of layers (4, 6, ... 24 and more);
  • resistance to mechanical and climatic influences;
  • high density and reliability of installation.

The high frequency printed circuit boards are made of special materials and have stable performance. They are combined with conventional FR4, can be used for operation in the range from ten to hundreds of MHz, have high transmission line matching rates.

For production, fluoroplastics are most often used, which are processed in several ways:

  • tenting method;
  • positive combined.

The combined positive method has a difference: the presence of a phase of applying a metal resist to a copper surface. The production of high-frequency printed circuit boards by the tenting method greatly facilitates the production process, minimizes money and time costs.

A key feature of printed circuit boards: when creating multilayer dielectrics, laminates are used only as the outer layers, while the inner ones are filled with ordinary glass cloth epoxy materials.

A special class of printed circuit boards - with buried and blind holes. They are products with vias, which are made according to the technology:

  • drilling to depth with further metallization;
  • micro-Via;
  • through drilling and metallization of holes in “half-packs” with further general pressing of a multilayer printed circuit board.

In some cases, a combination of the above methods is used.

Rigid-flex and flexible printed circuit boards are manufactured using thin and flexible dielectrics, as well as separate designs. Indispensable in cases where high demands are made on heat removal, for example:

  • in engine control systems;
  • in power supplies, etc.

They are made on a metal base. In some cases, a printed circuit board is used, supplemented with a metal core and a thick heat-dissipating layer.

Recently, planar transformers have been actively produced, which are separate MPPs and trace elements as part of multilayer printed circuit boards, where the tracks on the PCB play the role of transformer windings or chokes. They are made in the classic way and are separated by layers of insulating material. This allows you to achieve:

  • small overall dimensions;
  • excellent performance;
  • high reliability;
  • repeatability of characteristics from product to product.

The PCB technology company is engaged in the production and supply of high-quality printed circuit boards of various types.


2 Comments

  • 21 Aug 2020 ShawnEdges

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    工具

    一种钓鱼竿机械部分示意图
    最基本的钓具包括:鱼竿、鱼线、鱼钩、沉坨(又名沉子)、浮标(又名鱼漂)、鱼饵。<>]:1其他辅助钓具包括:失手绳、钓箱、线轮、抄网、鱼篓、渔具盒、钓鱼服、钓鱼鞋等。<>]:1

    钓竿一般由玻璃纖維或碳纖維轻而有力的竿状物质製成,钓竿和鱼饵用丝线联接。一般的鱼饵可以是蚯蚓、米饭、蝦子、菜叶、苍蝇、蛆等,现代有专门制作好(多数由自己配置的半成品)的粉製鱼饵出售。鱼饵挂在鱼鉤上,不同的對象鱼有不同的釣組配置。在周围水面撒一些誘餌通常会有較好的集魚效果。

    钓具
    鱼竿
    主条目:鱼竿
    钓鱼的鱼竿按照材质包括:传统竹竿、玻璃纤维竿、碳素竿,按照钓法包括:手竿、矶竿、海竿(又名甩竿),按照所钓鱼类包括:溪流小继竿、日鲫竿(又名河内竿)、鲤竿、矶中小物竿。<>]:6-8

    鱼钩
    主条目:鱼钩
    鱼钩就是垂钓用的钩,主要分为:有倒钩、无倒钩、毛钩。<>]:14

    鱼线
    主条目:鱼线
    鱼线就是垂钓时绑接鱼竿和鱼钩的线,历史上曾使用蚕丝(远古日本)、发丝(江户时期日本)、马尾(西欧)、二枚贝(地中海)、蛛网丝(夏威夷)、琼麻(东南亚)、尼龙钓线(美国)。<>]:25

    鱼漂
    主条目:鱼漂
    鱼漂又名浮标,垂钓时栓在鱼线上的能漂浮的东西,主要用于搜集水底情报,查看鱼汛,观察鱼饵存留状态,以及水底水流起伏变化。<>]:36

    鱼饵
    主条目:鱼饵
    鱼饵分为诱饵和钓饵,是一种用来吸引鱼群和垂钓时使用的物品,钓饵分为荤饵、素饵、拟饵、拉饵。<>]:170

    沉子
    主条目:沉子
    沉子又名沉坨、铅锤,是一种调节鱼漂的工具。<>]:45

    卷线器
    主条目:卷线器
    卷线器主要安装在海竿和矶竿上的一种卷线的工具。<>]:63

    连结具
    主条目:连结具
    连结具是连结鱼线与钓竿、母线与子线的一种连结物,使用最广泛的是连结环。<>]:55

    识鱼
    鱼类的视力不如人类,距离、宽度均无法和人类的视力比较,鱼类对水色、绿色比较敏感,鱼类的嗅觉非常灵敏,鱼类的听觉也非常灵敏,钓鲤鱼时,不能在岸上大声谈笑、走动不停,鱼类的思考能力非常弱,鱼类应对周边环境随着气象、水温、水色、潮流、流速、水量的变化而变化,于是便出现了在同一个池塘、水库、湖泊,往日钓鱼收获大,今日少,上午收获大,下午少,晴天大,雨天少等情况。<>]:114-117淡水钓鱼,中国大陆经常垂钓的鱼类对象是本地鲫鱼、日本鲫、非洲鲫、鲤鱼、游鱼、罗非鱼、黄刺鱼(黄鸭叫)、黄尾、鳊鱼、青鱼、草鱼、鲢鱼、鳙鱼,台湾经常垂钓的鱼类对象是本地鲫鱼、日本鲫、吴郭鱼(罗非鱼)、溪哥仔和红猫(粗首马口鱲)、斗鱼、罗汉鱼、苦花、三角姑(河鮠)、竹蒿头(密鱼)。<>]:117

    影响鱼类的6大因素主要是:季节变更、气温高低、水的涨落、风的大小、水的清浊、天气阴晴

  • 21 Aug 2020 BrandonFielo

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