PCB, Double panel (Double - Sided Boards) on both sides of the wiring. But you have to use both sides of the wire, you must have appropriate circuit connection between two sides. This circuit is called the "bridge" between the guide hole (via). Guide hole is on the PCB, or coated with metal small hole, it can be connected to both sides of the wire. Because the area of the double panel a times larger than a single panel, and because the wiring can cross (round to the other side), it is more suitable for use in more complex than a single panel circuit.
Technically double panel is a kind of PCB circuit board is very important in, he is the purpose of the great, to see if a board PCB board double panel is simple, understanding of a single panel is completely believe friends can grasp, is an extension of the single panel, double panel means single panel line enough to go to the opposite, there are important features of double panel, there is a guide hole. Simple point said is double line, both sides have a line! A summary is: double walk line board is double panel! Will ask some friends such as a piece of board double line, but only one side have electronic parts, such as plate is double side or single panel? The answer is obvious, the board is double panel, just in the double panel plate on the parts.