The design of the printed circuit board is based on the circuit schematic diagram to realize the functions required by the circuit designer. The design of the printed circuit board mainly refers to the layout design, and the layout of external connections needs to be considered. Various factors such as the optimal layout of internal electronic components, the optimal layout of metal connections and vias, electromagnetic protection, heat dissipation, etc. Excellent layout design can save production costs 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 by computer-aided design (CAD).