top layer of the PCB and has the role of a reference indicator for the components on the PCB. Graphics and text on a circuit board's PCB are usually printed with a non-conductive permanent epoxy ink. The color is usually white, although HASL other colors are available: yellow,
using traces of one or more layers HASL of copper sheets laminated on and/or between layers of conductive substrate sheets. A printed circuit board can have several layers of copper which are almost always arranged in pairs. The number of layers and the designed interconnection between them (vias,
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 like an ink and is applied in a thin layer similar HASL to varnish on the entire surface of the printed circuit less on the soldering pads and it