I’ve been wondering this for years. Like, I look at a motherboard and think, okay, this motherboard connects all pieces together. But HOW?! Watching a video of machines solder small bits of metal onto a board doesn’t help me understand it.
How does each individual piece get made first? It all just looks like metal to me. If you were to make a motherboard from scratch, what would the process be?
In: Technology
Components like ICs, resistors, capacitors and everything else you see on a PCB are made separately. The same components can be used for all kinds of things – not just the computer you are looking at.
Electrical Engineers work on first creating a schematic that lays out what needs to be connected to work, they’ll test it etc, and then translate it into a PCB layout. There they design the physical layout that you see – there are PCBs in pretty much everything electronic – they can be very small or very large. It’s purpose (the PCB) is to provide electrical connections between components. It’s actually a lot more complex than that, but fundamentally it’s its purpose.
While you didn’t ask specifically, you should know that there’s a lot more to a PCB than you can see with your eyes. Most motherboards have 4 or 8 layers – meaning there’s a ton of connections you cannot see. Still the idea is to connect everything with the right electrical and thermal properties so it will work. In your computer, you want the CPU connected to memory, the PCI bus which connects to sound, network, video and more – it’s all about connections and electricity, and dealing with the heat that it generates.
Before we had PCBs you would see a nest of wires connecting everything. It didn’t take a lot of components before that was just a big mess hard to figure out. It is however doing exactly what the PCB does – connect things electrically. If you google “wire wrap” you’ll see early designs of computer components where it’s nothing but a lot (thousands) of little wires that are dragged from component to component. This was done MANUALLY and was considered a job for mainly women as they were seen as having steadier and more nimble hands. PCBs today are mostly soldered and fabricated entirely by machines – it’s designed on a computer and robots and machines create the PCBs, put the solder and components on, solder (using heat – not from a soldering iron), and test it before it leaves the factory. No human touch needed at all.
The solder is electrically conductive. Today most components are what we call “surface mount” and the solder connects the little legs/edges (lots of components have connections on the bottom that you cannot see) on the component to the surface of the PCB where the track (the thing that is conductive) and because it’s conductive it’s a good connection. Some components are still thru-hole meaning they have legs that go through little holes in the PCB, and the solder holds them in place while also ensuring there’s connectivity between the pin that goes into the hole, and the track that the hole is part of. It simply connects the PCB to something else. It’s like glue, but glue that conducts electricity.
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