Fundamentals of the PCB design – An overview

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A PCB or printed circuit board is a copper, non-conductive, and rugged structure based on substrate meant for connecting electrical components. A common example would be the green boards that we generally see inside regular electronic devices and appliances. These circuit boards are the very backbone of every device that allows the passive parts (like inductors, resistors and capacitor), active components (like operation amplifiers) and other embedded devices to connect with each other into a specific form to create a design that fits the needs of the product. Copper connections also known as route is what connects these components together. These routes act like the passageway through which electrical signals flow. The first ever PCB was developed by Paul Eisler, who was an Austrian engineer. He was born in Vienna, and during the World War II he earned several patents in terms of etching processes, that defined conduits and routes on the board. The flow of PCB design comprises four different stages. The first phase deals with research and selection, while the second phase is about simulation and schematic capture. This is followed by board layout, and board verification. All these four stages are crucial in every electronic product design. A typical printed circuit board would consist of several copper layers that provide room for electrical signals. It also has several dielectric layers meant for insulation. The common green color that is present on most PCBs comes from solder mask. However, it is not a rule of thumb that the solder has to be green. It can be red and blue as well. During the designing process a PCB’s board outline can be cut up in various shapes to get a product that meets a certain design requirements. For small devices, specific shapes like rectangular, zigzag and round are quite crucial before finalizing a product. There are several methods that are deployed to decide the board outline that includes DXF files (a CAD tool). The copper routes that conduct electrical signals to connect are created by layering the copper on board surface followed by etching process. The etching is done by putting a mask on the copper route areas and removing unwanted copper. To create regions that attach different components on a board, holes are drilled. A PTH or plated through hole on the board is called via which allows formation of electrical connection between multiple copper layer.