PCB Design Basics
What actually happens between a breadboard prototype and the finished, professional-looking board your project ships on.
A breadboard (Lesson 15) is perfect for prototyping, but it's bulky, its connections can work loose, and it's not something you'd want to ship inside a finished product. A printed circuit board (PCB) replaces those breadboard wires with permanent copper traces etched onto a rigid fiberglass board, with components soldered directly to fixed pads.
Designing a PCB happens in two stages using free software (KiCad and EasyEDA are popular starting points). First, you draw a schematic — the same kind of circuit diagram from Lesson 5, showing every component and how they're electrically connected, without worrying about physical placement yet. Second, in layout, you arrange the actual component footprints on a board outline and draw the copper traces between them, guided by the connections your schematic already defined.
A few concepts you'll run into quickly in layout:
- Trace width — wider copper traces carry more current safely; power traces are usually drawn wider than signal traces.
- Via — a small plated hole that connects a trace from one copper layer to another, since most boards have copper on both the top and bottom (or more layers, for complex boards).
- Ground plane — a large, solid area of copper connected to ground, which reduces electrical noise and simplifies routing (you'll see why noise matters in the next lesson).
- Silkscreen — the printed labels and outlines on the board's surface, purely cosmetic and informational, helping you (or anyone assembling the board) identify components.
Once the layout is finished, you export manufacturing files and send them to a PCB fabrication house, which etches, drills, and plates the board before shipping it back ready for you to solder your components onto.