Why does the resistivity of semiconductor go down with temperature？Between the conductor and semiconductor resistivity difference is due to the different density of charge carriers.
Reasons for blistering of multilayer circuit board
At present, most of the holes drilled in the double-sided flexible printed board are still drilled by the NC drilling machine. The NC drilling machine is basically the same as that used in the rigid printed board, but the drilling conditions are different. Because the flexible printed board is very thin, multiple pieces can be overlapped for drilling. If the drilling conditions are good, 10 ~ 15 pieces can be overlapped for drilling.
PCB manufacturers show you the evolution of PCB production process. In the 1950s and early 1960s, laminates mixed with different types of resins and various materials were introduced, but PCB is still single-sided. The circuit is on one side of the circuit board and the component is on the other side. Compared with the huge wiring and cable,
Printed circuit board (PCB) is a board made of insulating and heat-insulating materials with a certain strength, which is fixed in the circuit and provides the connecting circuit between various components.
