PCB is the short name for printed circuit board; it will be used on nearly every electronic products. If there are any e-parts on the equipment, then the parts will be soldered on different size of PCBs. In addition to fixing variety small components, the main function of PCB board is providing mutual electronic connection for all parts on it. The traces on PCB board become denser and denser with the development of electronic products. The blank PCB (no components on it) is called printed wiring board (PWB) also. The raw material of printed circuit boards are insulation and uneasy to be bent. The tiny wiring material is copper foil we can see from the surface of PCB raw material, and the copper foil is covering the whole board at the very beginning, while they will be partial etched during the production, and the remained part forms tiny circuits. Those circuits are named as conductor pattern or wiring, and will be used for providing electronic connection for the components.

Normally the PCB boards are green or brown, and it’s the color of solder mask. PCB solder mask is an insulation protecting layer for copper wirings; it can also protect the components from mis-soldering. There is another layer --- silk screen on the top of solder mask layer, and it will be printed with legend or marks (usually to be white), to mark the position of each components.

The various parts of printed circuit board (PCB) have following features:
Pads: It’s the plated hole used for welding pins of components.
Via hole: It’s the plated hole used for connecting components between layers.
Mounting hole: It’s used for fixing the PCB board
Wire: It’s the electrical network copper foil used for connecting the components’ pins.
Connector: It’s the part used for connecting of PCBs.
Padding: It’s the copper used for ground network, and it can reduce the impedance efficiently.