PCB legend, also known as PCB component overlay or PCB silkscreen legend, is an important aspect of printed circuit board design. It consists of text and graphical symbols that are printed on the surface of the PCB. The main role of the PCB legend is to provide information about the components and their locations on the PCB. It helps in the assembly process by allowing technicians to quickly identify where each component should be placed. For example, the legend will show the position of resistors, capacitors, integrated circuits, and other components with their corresponding designators.

　　The PCB legend can also include additional information such as the polarity of components. For polarized components like diodes and electrolytic capacitors, the legend will indicate the correct orientation. This is crucial as incorrect placement of polarized components can lead to malfunction or even damage to the PCB. the legend can provide information about test points, jumper settings, and other important features of the PCB. It serves as a reference guide for troubleshooting and maintenance.

　　The design of the PCB legend should be clear and legible. The font size and style should be chosen to ensure easy reading, especially considering the small size of many PCBs. The legend should also be positioned in a way that does not interfere with the functionality of the PCB or the placement of components. In some cases, the legend may need to be updated or modified during the design process to reflect changes in the PCB layout or component selection. the PCB legend is an essential communication tool between the PCB designer and the assembly and maintenance personnel, facilitating the correct and efficient handling of the printed circuit board.