Printed circuit board design is based on circuit picture shows the basis for the circuit designer to achieve the functionality required. Printed circuit board layout design mainly refers to the need to consider the layout of external connections, internal electronic components of the optimal layout, interconnect and optimization of hole layout, Dianci protection, heat dissipation and other factors. Good layout can save production costs, achieve good circuit performance and heat dissipation. Simple layout can be achieved by hand, require complex layout using computer-aided design (CAD) to achieve.