is generally green in color but can have different colors: green, conditions and Terms red, blue, white, black. Only the outer layers need to be covered with solder mask, the inner copper layers are protected by the adjacent substrate layers. The soldering mask soldermask is made of a fluid substance
board's PCB are usually printed with a non-conductive permanent epoxy ink. The color is usually white, although other colors are available: yellow, black, blue, red. Screen printing is used conditions Terms and to render useful information on the PCB board that can help users during assembly. It is used to mark component values, part numbers, test points,
board), or multi-layered (outer Terms and conditions and inner layers of copper alternating with insulating layers). Among the multi-layer PCBs, the most common are the four-layer ones. The four-layer board has many more routing options in the internal layers compared to the two-layer board, and often part of the internal layers are used as a ground plane