What is the most important difference between the PCB board and the second floor?
The simplest difference is that the four-story board has an inner layer and the second board does not.
Speak, is the four-layer board has the inner layer, in terms of the process will be through the inner layer of some of the etching, after pressing to suppress.
Four-layer board is in the double-sided board (two-layer board) on the basis of another after the press, when the pressure will be on both sides of the double-sided plate with PP and copper, and then after high temperature and pressure into a multi-layer board.
