pcb-basics

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pcb-basics [2020/03/31 09:37] benhpcb-basics [2021/01/13 20:01] benh
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-**What is a PCB?**\\  +**When do I need a PCB?**\\  
-A PCB (//printed circuit board//, or just “board”)is physical method by which circuit designers can mount components with connections between them to replace a breadboard circuit or wire-wrapping. +{{ :img_3259.jpg?nolink&400|breadboard may be used for prototyping before a PCB is fabricated}}Before fabricating PCB, a circuit is often built using a breadboard or wire-wrapping technique to make sure that it works. While suitable for prototyping or proof-of-concept, breadboards and wire-wrapping methods should usually be 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.
  
-{{http://manage.pcbgogo.com/img/js/ueditor/ueditor1.4.3.3/net/upload/image/20190923/6370485921386000002179968.png|This is a PCB}}+If you don't have time to design and manufacture a PCB, you may want to consider using a perfboardA perfboard is a rectangular sheet covered in a grid of through holes that can be used for solderingHoles are connected by either running a wire between them or by making a solder bridgeMany also include pads on the side for surface mount componentsPerfboards are more durable than breadboards and can save time when only one or two designs are neededHowever, they are not recommended for circuits that are complicated or need to be replicated many times.
  
-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 rigidelectrically isolated backingonto which you can solder components and cut connections between them out of the copper. More complex //stackups// (that is, the layering of the PCBcan include multiple copper layersdifferent insulating layers, and moreConnections 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//+The rest of this article focuses on PCBs. If you are not sure which method 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. 
 + 
 +{{http://manage.pcbgogo.com/img/js/ueditor/ueditor1.4.3.3/net/upload/image/20190923/6370485921386000002179968.png?500 |This is a PCB}} 
 + 
 +**What 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. Let's step though that definition: 
 +  * //Multi-layered substrate - // A PCB starts as a sheet of layered material. This conmanly consists of a thin layer of copper on the bottoma substrate called FR4 (FR5 is also common), and another thin layer of copper. You might have seem these sheets sitting below the Hive's milling machine (ProtoMat). 
 +  * //Designed and fabricated - // The first step in making a PCB is to design it using CAD (computer-aided design) software. Popular CAD tools include Eagle, Kicad, and Altera. The next step is to physically create the PCBreferred to as fabrication. 
 +  * //Eliminate wiring - // While the copper layers are electrically conductive, the FR4 is not. That means that by removing //(etching away)// copper, you leave behind a pattern that directs the flow of electricityThese copper connections //(traces)// electrically connect components exactly as wires do. 
 +  * //Mechanically support - // Unlike flexible wires, a rigid PCB can be used to connect //(mount)// components, such as resistors or chips. This is typically achieved through some form of soldering, in which a conductive metal "glue" to attach components to the PCB. 
 + 
 +Traces on different copper layers can be connected by adding //vias//, which are holes drilled into the board and filled with a conductive metal, often copperThe process is known as //electroplating//. Electroplating covers every exposed inch of a surface in a thin layer of copper. This means that via drilling and electroplating should be done before etching traces. At the Hive, the process takes two hours regardless of board design. More complex //stackups// (that is, the layering design of the PCB) can include more than two copper layers, different insulating materials, and more. Many PCBs you will come across are covered in a resin-based material, which is often green. This is called //soldermask//, and it can be added to isolate traces beyond just etching. You may also notice the presence of text and images, which is added using a //silkscreen//
  
 <<Image of a PCB>> <<Image of a PCB>>
 <<Labeled image of a PCB> <<Labeled image of a PCB>
 <<Stack up of a 2 layer board>> <<Stack up of a 2 layer board>>
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 **How do I make a PCB?**\\  **How do I make a PCB?**\\ 
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   - 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.    - 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. 
- +  - 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 "[[pcb-fab|The Official Fabrication Guide]]" page for step-by-step details.
-  - 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-pcb|How to make a PCB at The Hive]]" page for details. +
   - 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.    - 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. 
  
  • pcb-basics.txt
  • Last modified: 2021/01/23 20:37
  • by madeline