What is a PCB?
瀏覽次數：1567 時間：2017-07-28
The abbreviation of printed circuit board is PCB circuit board. Its Chinese name is printed circuit board, also known as printed circuit board and printed circuit board. It is not only a very important electronic component, but also the support of electronic components, but also the provider of electrical connection of electronic components. But because it is made by electronic printing, it is also called "printed" circuit board. Its development has a history of more than 100 years; Its design is mainly layout design; The main advantage of using circuit board is to greatly reduce wiring and assembly errors, and improve the automation level and production labor rate.
PCB history
His inventor was Austrian, Paul Eisler (Paul Eisler), he used printed circuit board in a radio device in 1936. By 1943, Americans widely used this technology in military radios. In 1948, the United States officially recognized this invention for commercial use. It was not until the mid-1950s that printed circuit board technology began to be widely used. Before the emergence of printed circuit board, electronic components The interconnection between them is realized by direct connection of wires. Now, the circuit panel only exists as an effective experimental tool; It has occupied an absolute dominant position in the electronic industry. PCB design the design of printed circuit board is based on the circuit schematic diagram, which realizes the functions required by the circuit designer. The design of printed circuit board mainly refers to layout design, which needs to consider various factors such as the layout of external connections, the optimal layout of internal electronic components, the optimal layout of metal wires and through holes, electromagnetic protection, heat dissipation and so on. Excellent layout design can save production cost and achieve good circuit performance and heat dissipation performance. Simple layout design can be realized by hand, and complex layout design needs to be realized with the help of computer aided design (CAD).
PCB classification
In terms of the number of layers of road board, it can be divided into single panel, double-sided board, four layer board, six layer board and other multi-layer circuit boards. The most important are the following three: 1 Single sided boards are on the most basic PCB. The parts are concentrated on one side and the wires are concentrated on the other side. Because the wires only appear on one side, this kind of PCB is called single sided. Because single panels have many strict restrictions on the design circuit (because there is only one side, the wiring cannot cross and must be routed around a separate path), this kind of board is only used in early circuits. 2. Double sided boards have wiring on both sides of this circuit board, but to use wires on both sides, it is necessary to have appropriate circuit connections between the two sides. This kind of "bridge" between circuits It is called via. A via is a small hole filled or coated with metal on a PCB. It can be connected with wires on both sides. Because the area of a double-sided board is twice that of a single panel, and because the wiring can be staggered (can be wound to the other side), it is more suitable for more complex circuits than a single panel. 3. Multilayer board (multi layer boards) in order to increase the area that can be wired, multi-layer boards use more single or double-sided wiring boards. One printed circuit board with both sides as the inner layer, two printed circuit boards with one side as the outer layer, two printed circuit boards with both sides as the inner layer and two printed circuit boards with one side as the outer layer are formed by alternating them through positioning system and insulating bonding materials, and the conductive graphics are interconnected according to the design requirements It is a four layer and six layer printed circuit board, also known as multi-layer printed circuit board. The number of layers of the board represents several independent wiring layers. Usually, the number of layers is even and includes the outermost two layers. Most of the main boards have a 4-8-layer structure, but technically, nearly 100 layers of PCB can be achieved in theory. Most large supercomputers use multi-layer mainboards, but because such computers can be replaced by clusters of many ordinary computers, super multi-layer boards have gradually been abandoned. Because all layers in the PCB are closely combined, it is generally not easy to see the actual number. However, if you carefully observe the motherboard, you can still see it. Classified according to hardware and software: divided into ordinary circuit board and flexible circuit board.
