What is a PCB?
First things first, PCB stands for printed circuit board; it's important to avoid being the "ATM Machine" person who says "PCB Board". They are the backbone of the electronics that we use in our everyday life, and, believe it or not, they aren't too complicated. At a high level, PCBs are usually made of FR-4, they can be almost any shape or color, and they are made up of layers. A simple board may have two or four layers, while more complex boards can get into the double digits, and layers can help you connect more signals to each other. Traces, or the internal wires that connect pieces, cannot cross each other on a single layer without creating an electrical short, so they need to go through vias, tunnels on the board, to a new layer. Think of it like designing a road system where you aren't allowed to use any intersections; the only solution becomes tunnels and overpasses, and you have the structure of a PCB.
This begs the question, what are we connecting? A PCB is used to connect components to create circuits. For example, resistors can be used to create filters or make circuits safer, capacitors store energy in a way similar to a battery, headers provide connection points so you can connect different circuits together, and integrated circuits (ICs) are tons of little parts in a specialized black box. On the FANTM DEVLPR we have ICs that amplify the signal coming from your arm, function as a power source, and filter EMG. Interestingly, there's currently a global IC shortage and it's affecting everyone from major car manufacturers to FANTM. All of these components are connected by traces, allowing electricity to flow through them. They are mechanically and electrically attached with solder to small pads on the board. Usually these pads come in one of two varieties: surface mount technology (SMT) or through hole technology (THT). The naming scheme is a bit verbose, SMT refers to components that are attached to a single layer of the board and THT components have legs that go straight through the board.
PCBs are essential in creating reproducible and easily modularized circuits that you find in everything from your headphones to your cat's water fountain. While designing them requires a certain level of technical expertise, understanding the basics is a little more straightforward. Next week we're going to be peeling back one more layer (pun intended) of how to go from idea to finished PCB. Hopefully, by the time we are done the whole process will be a little more tangible. Please comment or email us with any questions you might have, and check back next week for more PCB talk. 💪🤖