Some parts of a circuit board include the board itself made from epoxy, paper, glass fiber or phenolic resin, traces made of copper, electronic components that have an unusual shape, and connectors that provide electrical signals and electricity to the board. The circuit board also comprises of vias filled with a metal plug capable of conducting electricity.
The board of the circuit board is usually 1.6 millimeters in thickness. Boards made from paper and resin are normally brown in color whereas, those made of glass fiber or epoxy are blue, green or red in color. These materials can be drilled into and cut, and can withstand electrical, temperature and mechanical stresses for long periods.
The board has a copper foil stuck to one or both sides. This foil is printed according to a pattern, and the portions that are exposed are removed chemically. This leaves thin lines on the board that are conductive. Termed as traces, these lines constitute the wiring of the circuit board and are used as connectors, tiny antennas or heat sinks.
The electronic components are soldered to the traces, and holes are formed into the board to accommodate them. The board's plastic connectors come with pins and inserts made of metal. The connectors are attached to the board via their pins that are soldered to the traces.
In circuit boards with layers of traces, the latter are connected through vias or holes made into the board. Metal plug is then filled into the vias. These boards have a high circuit density rendering them useful for making small electronic devices such as mobile phones and mp3 players.