In a world where modern technological inventions are regularly updated, there is probably one thing that remains a constant, and that is the printed circuit boards that lie at the heart of every piece of electronic device. Also referred to as the PCB, these boards are responsible for modernizing the way that wires are interconnected inside electronic devices. And the invention of the PCB has made it possible for people to move on from the bulky walkman to the more compact mp3 players, or from the bulky black and white TV with a knob for changing channels to the elegant flat smart TV that has more capabilities and can be controlled with just the flick of a wrist.
All this modernization was made possible because printed circuit boards have eliminated the need for having too many electrical wires. This means wire junctions are also no longer necessary, leaving some space inside the device that can either be used for a different purpose or left out entirely on the new design. The PCB itself also underwent a lot of changes from the first time it was introduced. Whereas before the schematic diagram on the PCB was imprinted manually on every board, now the diagrams are already pre-installed on computer systems that feed this information to machines that automatically imprint the diagram on hundreds of boards. This automation sped up the process of creating printed circuit boards, thereby shortening the timeframe between new product roll-outs.
In trying to understand the process of creating printed circuit boards, it should first be understood that there are three primary types of PCBs, namely:
1. Single-sided PCBs – these PCBs only have one sheet of laminated copper where the components are attached on one side of the substrate, while the electronic conductors are attached to the other side.
2. Double-sided PCBs – these PCBs contains 2 layers of laminated copper sheets that are each located on either side of the substrate. This double-layer allows engineers to hook in more complex wiring patterns that give the device its multi-functional capabilities.
3. Multi-layer PCBs – based on the term itself, these printed circuit boards consist of multiple layers of laminated copper sheets with complex design patterns and even more complex sets of wirings. Multi-layer circuit boards are normally made by sticking several pieces of double-sided PCBs together.
Because double-sided and multi-layer PCBs are connected to multiple conductor patterns, pathways are required to connect one conductor pattern to another. The pathways are referred to as ‘vias’ and these act as conduits for electronic signals to go through. Double-sided PCBs only require one via to connect the patterns. Multi-layer PCBs often need multiple vias that would distribute power to the various connector patterns throughout the board.
However, since vias also take up much-needed space on the boards, electronic engineers have designed a way of connecting vias without having to penetrate layers of the board that are have no connection to the vias. This can be achieved by utilizing either of the following vias:
Blind vias – these vias connect only one external layer to multiple inner layers without unnecessarily going through the entire circuit board.
Buried vias – these vias are packed in-between two internal layers without penetrating the external layer or any point on the surface of the circuit board.
Vias and multiple layers are the prime examples of how technology has developed throughout the years. These are the proof that the PCB has undergone a lot of improvements from being the original single-layer circuit board that was introduced in the latter part of the last century.