Printed circuit board, also known as the Printed Circuit Board, the electrical connection of electronic components provider. Its development over 100 years of history; it is designed mainly to layout; The main advantage of using the circuit board layout and assembly is greatly reduced errors, increased level of automation and production and labor rates.
　　Printed Circuit Board using the main advantages are:
　　1. As the graph has a repeatability (reproducibility) and consistency, reducing wiring and assembly errors, saving on equipment maintenance, testing and inspection time;
　　2. Design can be standardized, beneficial exchange; PCB
　　3. Wiring density, small size, light weight, which will help the miniaturization of electronic devices;
　　4. Conducive to mechanization and automation of production, increased labor productivity and lower cost of electronic equipment.
　　Printed circuit board design is based on circuit picture shows the basis for the circuit designer to achieve the required functionality. Printed circuit board layout design mainly refers to the need to consider the layout of the external connection, optimize the layout of the internal electronic components, metal wires and vias to optimize the layout, electromagnetic protection, heat dissipation and other factors. Excellent layout can save the cost of production to achieve a good performance and cooling circuit performance. Simple layout can be achieved by hand, need the help of complex computer-aided layout design (CAD) to achieve.
　　Printed Circuit Board manufacturing methods can be divided into minus method (Subtractive) and the addition method (addition method) two categories. Currently, large-scale industrial production minus the law or in the main method of corrosion of copper.