Printed Circuit Boards

Printed circuit boards are also known as by the abbreviation PCB. These boards are used as the physical support for electronic components. They are also used to provide the electrical current from beginning to end of the circuit on the board.

The printed circuit boards use conductive pathways, or traces, etched from copper sheets laminated onto a non-conductive substrate. Some of the other names that you might run into during your study of printed circuit boards are: printed wiring board (PWB); etched wiring board (EWB).

Once the electronic components have been attached to the bare boards, the item becomes known as a printed circuit assembly (PCA), also known as a printed circuit board assembly (PCBA).

There are many benefits to printed circuit boards. They are rugged, inexpensive, and are highly reliable. They require much more layout effort and higher initial cost than either wire-wrapped or point-to-point constructed circuits, but are much cheaper, faster, and consistent in high volume production.

The vast majority of printed circuit boards are composed of between one and twenty-four conductive layers. These layers are separated and supported by layers of insulating material which is then laminated together.

Layers may also be connected together through drilled holes called vias. The holes are either electroplated or small rivets are inserted which can provide for an electrical connection. More often than not the holes are drilled through the entire board as this is easier and cheaper. The exceptions to this are the so called high-density printed circuit boards, which may have blind vias or buried vias.

It is interesting to note that the vast majority of printed circuit boards are made by applying a layer of copper over the entire substrate, sometimes on both sides. This creates a blank PCB. Once this is completed, the process of removing unwanted copper begins. As the copper is removed, only the desired copper trace paths are left.

The reverse process is possible also. A few printed circuit boards are made by adding traces to the bare substrate (or a substrate with a very thin layer of copper) usually by a complex process of multiple electroplating steps. As you might imagine, this process is more time consuming and more expensive.

A good way to learn more about printed circuit boards is to buy a simple kit and assemble your own board. These kits are very inexpensive and they can be assembled with only a few common tools. You will most likely need a good soldering iron in order to complete the project.