pcb-basics

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This page will go through the basics of what a PCB actually is, along with definitions and examples of many of the terms used with PCBs. Design is looked at on our “PCB Design” page.

What is a PCB?
A breadboard may be used for prototyping before a PCB is fabricatedA PCB (printed circuit board, or just a “board”), is a physical method by which circuit designers can mount components with connections between them. Before fabricating a PCB, a circuit is often built using a breadboard or wire-wrapping to make sure that it works. While suitable for prototyping or proof-of-concept, breadboards and wire-wrapping methods are usually avoided in final products, as they are prone to loose connections, misaligned pins, and other issues. Furthermore, properly designed PCBs can support electrical characteristics that other methods cannot.

If you don't have time to design and manufacture a PCB, you may want to consider using a perfboard. A perfboard is a rectangular sheet covered in a grid of through holes that can be used for soldering. Holes are connected by either running a wire between them or be making a solder bridge. Many also include pads on the side for surface mount components. Perfboards are more durable than breadboards and can save time when only one or two designs are needed. However, they are not recommended for circuits that are complicated or need to be replicated many times.

The rest of this article focuses on PCBs. If you are not sure which technique for implementing your circuit design is best for your project, you can talk to a PI about the advantages and disadvantages of different methods. Keep in mind that for most projects, you will use multiple implementation methods as you develop your design.

This is a PCB

A PCB is a multi-layered substrate specially designed and fabricated for circuit designers to eliminate wiring and mechanically support their components. At their simplest, they are single layers of copper on a rigid, electrically isolated backing, onto which you can solder components and cut connections between them out of the copper. More complex stackups (that is, the layering of the PCB) can include multiple copper layers, different insulating layers, and more. Connections between components are called traces. Traces on different copper layers can be connected by adding vias, which are holes that are drilled into the board and electroplated to make a conductive pathway. Soldermask can be added to isolate traces beyond just etching. Text and images can be added with silkscreen.

«Image of a PCB» «Labeled image of a PCB> «Stack up of a 2 layer board»

How do I make a PCB?
Making a PCB is done in three overarching steps: design, fabrication, and assembly.

  1. Design: Typically, one starts by developing a circuit, which may include simulations and/or prototyping on breadboard. The design of the board itself is then done on the computer using electronic computer-aided design (e-CAD) programs, such as KiCAD, EAGLE, or Altium, though there are many others.
  2. Fabrication: There are a number of different steps, depending on the complexity of your design, but a standard 2-layer board without vias begins by drilling any necessary holes, followed by etching/isolating the traces and components, and finally routing/cutting the board out. Soldermask and silkscreen can be applied after the board has been fabricated. See our “How to make a PCB at The Hive” page for details.
  3. Assembly: the process of actually adding the components to the fabricated PCB. At The Hive, we have soldering stations to facilitate this, as well as solder paste and a reflow oven if you'd prefer. We can also make solder paste stencils.

Glossary
Trace
Via
Pitch
Mil
Etch
Electroplate
Route (cut vs route traces)

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  • Last modified: 2020/05/21 21:12
  • by madeline