pcb-basics

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision
Previous revision
pcb-basics [2020/05/31 17:00]
madeline Step-through explanation of PCB definition
pcb-basics [2021/01/23 20:37]
madeline Added glossary definitions
Line 5: Line 5:
  
  
-**What is a PCB?**\\  +**When do I need a PCB?**\\  
-{{ :​img_3259.jpg?​nolink&​400|A breadboard may be used for prototyping before a PCB is fabricated}}A 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 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.+{{ :​img_3259.jpg?​nolink&​400|A breadboard may be used for prototyping before a PCB is fabricated}}Before fabricating a 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.
  
 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 by 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. 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 by 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.
Line 14: Line 14:
 {{http://​manage.pcbgogo.com/​img/​js/​ueditor/​ueditor1.4.3.3/​net/​upload/​image/​20190923/​6370485921386000002179968.png?​500 |This is a PCB}} {{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: 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 bottom, a 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).   * //​Multi-layered substrate - // A PCB starts as a sheet of layered material. This conmanly consists of a thin layer of copper on the bottom, a 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).
Line 20: Line 21:
   * //​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.   * //​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.
  
-More complex //​stackups//​ (that is, the layering of the PCB) can include ​multiple ​copper layers, different insulating ​layers, and more. Traces on different copper layers can be connected by adding //vias//, which are holes that are drilled into the board and electroplated to make conductive pathway. //Soldermask// can be added to isolate traces beyond just etching. ​Text and images ​can be added with //​silkscreen//​. ​+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 copper. The 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 electroplating 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 resin-based material, which is often greenThis 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>>​
- 
  
 **How do I make a PCB?​**\\ ​ **How do I make a PCB?​**\\ ​
Line 31: Line 31:
  
   - 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 our "[[how-to-pcb|How to make a PCB at The Hive]]" page for 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 "[[pcb-fab|The Official Fabrication Guide]]" page for step-by-step ​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. ​
  
 ** Glossary **\\ ** Glossary **\\
-Trace\\ +//​Substrate//​ - the material between the two copper layers, FR4 is common\\ 
-Via\\ +//CAD// - __c__omputer __a__ided __d__esign; refers to any software used for design (SolidWords,​ EAGLE, CST Studio, etc.)\\ 
-Pitch\\ +//Etch// - selectively removing copper to leave behind a conductive pathway in a specific shape\\ 
-Mil\\ +//Isolate// - electrically separating (isolating) two areas of copper, usually by etching\\ 
-Etch\\ +//Trace// - the copper path left behind after etching; traces function like wires\\ 
-Electroplate\\ +//​Soldering//​ - a technique used to create conductive connections between two components, usually in a circuit\\ 
-Route (cut vs route traces)\\ +//Via// - a small, copper-filled hole drilled through a PCB which connects two or more layers\\ 
 +//​Electroplating//​ - a chemical process that covers every exposed area of a PCB with a thin layer of copper\\ 
 +//Stackup// - a layered PCB design\\ 
 +//​Soldermask//​ - an insulating resin applied to protect the PCB and further isolate traces; often green colored\\ 
 +//​Silkscreen//​ - text printed on top of a soldermask to provide information about a PCB; often white colored\\ 
 +//Pitch// - the distance between the centers of two features, often the distance between the centers of two holes\\ 
 +//Drill hit// - another name for a drill hole\\ 
 +//Mil// - one-thousandth of an inch, a common imperial unit for small-scale designs\\ 
 +//Route// - a cutting process that removes the fabricated PCB from the rest of the substrate\\
  • pcb-basics.txt
  • Last modified: 2021/01/23 20:37
  • by madeline