We have just mentioned, the basic PCB, components concentrated in one side , wires are concentrated in the other side . Because the lead only in one side, so we call this is called single-sided PCB Single-sided). Single- panel design lines because there are many strict restrictions (because only one side , between wiring must not cross the path around alone ) , only the circuit until the early use of such a board .
2.Double- panel (Double-Sided Boards)
Both sides of this circuit board iring . But with a wire on both sides , both sides must be in the proper electrical connections between the Caixing . This circuit between a "bridge" is called the pilot hole (via). Pilot hole in the PCB, the holes filled or coated with metal , it can be connected with the wires on both sides . Because the two- panel single panel bigger area than doubled , and because routing can be interlaced (which can be around to the other side ), it is more suitable than the more complex single-sided circuit .
3 , multilayer (Multi-Layer Boards)
In order to increase the area available wiring , multilayer spend more single- or double-sided wiring board . Multilayer films using the number of two- panel , and in between each layer put a layer of insulation board after the firm adhesion ( laminated ) . Board represents the number of layers there are layers of separate wiring layers , usually layers are even, and contains the most lateral of the two . Most of the motherboard are 4 to 8 layers of structure , but technically can be done almost 100 layers of PCB board . Most large-scale use of supercomputers rather multi-layered board , but because these computers have been available to replace many common computer clusters , super- multilayer has been gradually being used . Because the PCB levels are in close combination , generally not easy to see that the actual number, but motherboard if you look closely , may be seen .
We have just mentioned pilot hole (via), if applied to double-sided board , then we are punctured and the entire board . However, in multilayer which , if you want to connect some of the lines , then the pilot hole may be a waste of space some of the other layer lines . Buried hole (Buried vias) and the blind hole (Blind vias) technology avoids this problem because they only penetrate several layers of them . Blind hole is to the surface layers of the internal PCB and PCB connections , do not have to penetrate the entire board . Buried inside the hole only to connect PCB, so the surface is just not apparent .
In multilayer PCB , the whole layer are directly connected to ground and power . So we will all levels of classification for the signal layer (Signal), the power level (Power) or the ground floor (Ground). If the PCB, parts require different power supply , usually have two or more of these PCB power and wire layer .