The circuit board miniaturizes and visualizes the circuit, and plays an important role in the mass production of fixed circuits and the optimization of the layout of electrical appliances. So how much do you know about circuit boards? The following is organized by learning friends about what is a circuit board, I hope everyone likes it!
Classification of circuit boards
The circuit boards are divided into three categories: single panel, double panel, and multilayer circuit board.
The first is a single panel. On the most basic PCB, parts are concentrated on one side, and wires are concentrated on the other side. Because the wires only appear on one side, this type of PCB is called a single-sided circuit board. Single panel is usually simple to make and low in cost, but it has the disadvantage that it cannot be applied to too complicated products.
Double-sided board is an extension of single-sided board. When single-layer wiring cannot meet the needs of electronic products, double-sided board is used. Both sides have copper clad and traces, and the lines between the two layers can be connected through vias to form the required network connection.
Multilayer board refers to a printed board with three or more conductive pattern layers and insulation materials laminated between them, and the conductive patterns between them are interconnected as required. Multilayer circuit boards are the product of the development of electronic information technology in the direction of high speed, multifunction, large capacity, small size, thinness, and light weight.
The circuit board is divided into flexible board (FPC), rigid board (PCB), and rigid-flex board (FPCB).
Circuit board compatible design
Electromagnetic compatibility refers to the ability of electronic equipment to work in a coordinated and effective manner in a variety of electromagnetic environments. The purpose is to make the electronic equipment not only suppress various external interference, make the electronic equipment work normally in a specific electromagnetic environment, but also reduce the electromagnetic interference of the electronic equipment itself to other electronic equipment.
1. Select a reasonable wire width. The transient interference caused by the printed circuit board PCB printed lines is mainly caused by the inductance component of the printed wire, so the inductance of the printed wire should be minimized.
2. Use the correct wiring strategy. Equal wiring can reduce the inductance of the wire, but the mutual inductance and distributed capacitance between the wires increase. If the layout allows, it is best to use a square grid wiring structure. Route the other side vertically, then connect them with metallized holes at the cross holes.
3. In order to suppress crosstalk between the conductors of the PCB circuit board, when designing the wiring, try to avoid long and equal routes, and open the distance between the wires as much as possible. cross. Setting a grounded printed line between some signal lines that are very sensitive to interference can effectively suppress crosstalk.
Composition of the circuit board
The circuit board is mainly composed of pads, vias, mounting holes, wires, components, connectors, padding, electrical boundaries, etc.The main functions of each component are as follows:
Pad: A metal hole used to solder component pins.
Vias: There are metal vias and non-metal vias. Metal vias are used to connect component pins between layers.
Mounting hole: used to fix the circuit board.
Wire: Copper film for electrical network used to connect component pins.
Connector: Components used for connection between circuit boards.
Filling: copper for ground network, can effectively reduce impedance.
Electrical boundary: It is used to determine the size of the circuit board. All components on the circuit board cannot exceed this boundary.
Advantages of circuit boards
Support for industrial policies
The outline of the “11th Five-Year Plan” for China’s national economic and social development proposes that the electronic information manufacturing industry should be enhanced, and core industries such as integrated circuits, software, and new components should be vigorously developed in accordance with the general trend of digitalization, networking, and intelligence.
According to the “Eleventh Five-Year Plan” for the development of information technology in China’s Ministry of Information Industry and the Outline of Medium- and Long-term Planning for 2020, printed circuit boards (especially multi-layer, flexible, flexible and flexible printed circuit board technology) are our electronics One of the 15 areas that the information industry will focus on in the next 5-15 years. Many circuit board technology parks have been established in Dongguan and Shenzhen.
Continuous and rapid growth of downstream industries
The rapid development of China’s information electronics industry provides a good market environment for the rapid development of the printed circuit board industry. The continuous increase in the output of electronic products such as electronic communication equipment, computers, and home appliances has provided a strong impetus for the rapid growth of the printed circuit board industry. In addition, the issuance of 3G licenses will trigger large-scale telecommunications investments and drive a large demand for servers, storage, and network equipment. According to the forecast of the Ministry of Information Industry of China, the growth rate of the fixed-asset investment scale of China Mainland Telecom in 2006 and 2007 will reach 10.53% and 14.29% respectively.
Labor cost advantages, manufacturing shift to China
As Asian countries’ preferential measures in terms of labor resources, markets, investment, and taxation policies have attracted US and European manufacturing to shift to Asia, especially China. China has unique conditions. A large number of electronic product and equipment manufacturers have set up factories in mainland China, which has led to the development of related industries. Printed circuit boards are used as basic electronic components, and the supporting demand for the market has grown strongly, and the industry has a promising future.
Disadvantages of circuit boards
High product homogeneity, low proportion of high-end boards, and weak cost passing ability
With fierce price competition, companies cannot pass on the rising cost factors to users. They can only rely on their own factors to digest. Under the situation of rising material costs, PCB prices will not change significantly. Once the cost of materials drops, the fierce Competition has brought prices down.
Local scale enterprise product structure and lack of key technologies
Small and medium sized companies and private production capacity and technological level are low product
It has not been internationally accepted industry standard
And the lack of their own recognized brand
Inadequate attention to research and development, inability to engage in R & D
Advanced equipment, technology and more in the hands of foreign companies
They did not form a fully furnished, industry self-regulation of the market
Waste disposal did not meet environmental standards
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