As the electronic equipment becomes more and more complex, more and more parts are needed, and the lines and parts of PCB are becoming more and more intensive.
The bare Board, which has no spare parts, is also often referred to as the Printed Wiring Board (PWB).
The substrate of the board itself is made of insulating and not easily bent material.
On the surface can see the fine line material is copper foil, originally copper foil is covered in across the board, and to get rid of the central in the manufacturing process of etching, stay part to turn into a network of fine lines.
These lines are called conductor patterns or cabling, and are used to provide circuit connections to parts on the PCB.
Usually the color of the PCB is green or brown, which is the color of solder mask.
It is an insulating layer that protects the copper wire and prevents the parts from being welded to the wrong place.
A silk screen is also printed on the resistance layer.
Usually it is printed with words and symbols (mostly white) to indicate the position of each part on the board.
Screen printing is also known as "legend".