Sep 6 2019
Your PC has worked well till now and all over sudden it’s gone blank and won’t turn on with all the DIY tricks you have learned from friends and the self-made computer gurus. Try a real computer wizard, and he’s likely to tell you that your PC’s Printed Circuit Board (PCB) has fallen flat. And now you’ve two problems instead of just one: you have a PC that’s dead and a long terminology that you know nothing about. Let’s see how we can help you get started with a straightforward guide to PCB design for beginners.
What is a PCB?
A Printed Circuit Board, at times referred to as a Printed Wiring Board, is a board that defines the function of an electrical or mechanical wire structure of the circuit. Most electronic or mechanical devices and appliances function thanks to the commands generated at the PCB. That implies that the PCB is the heart of these systems, and if the electronic circuits in these systems are not built on a sound PCB design or layout, the system will not work.
PCBs are made of materials that are nonconductors. Fiberglass is a good example of non-conducting material. On the PCB are circuits designed on the boards with copper tracks to allow the transmission of electrical commands from one part to another. By drilling holes on the board, the manufacturer can fix electronic components in their corresponding positions and solder them so that, together with the copper tracks, they form a complete circuit. The PCBs used in electronic appliances allow precise functioning, control, and monitoring of these appliances compared to other wiring options.
Parts of a PCB
The PCB has four main parts: the substrate, copper layer, solder mask, and silkscreen.
Substrate is made of fiberglass joined with epoxy and can be considered the skeleton of the board. It is used because it is non-conducting and can resist breakage.
The copper layer consists of a copper foil or copper coating. The purpose of this part is to transfer the electrical signals to and from the board. It could be described as the CNS of the PCB.
The solder mask is the PCBs protective skin. It is made of polymer and is meant to shield the copper layer from short circuits when it comes into contact with the environment.
The silkscreen is your guide for the PCB. If we were thinking of a graph, we could describe the silkscreen as your legend. It is on the side and has a layout with numbers of the different parts, their logos, component references, and symbols switch settings.
Luckily, most of us who use electronic devices don’t have to worry about the nuts and bolts of PCBs. But if you are an electronic or mechanical engineer, knowing about PCBs is the soul of your profession. There’s plenty you require to know, beginning with the basics of PCBs and PCB design.
What is PCB design?
If you have all the parts of a potential electronic device but are lacking the PCB, your device is as good as inexistent. The Printed Circuit Design brings to life your device. A layout software is used to convert the schematic diagram of your circuit into a PCB design layout. This implies linking components and routing to give form to electrical connectivity on a circuit board. The layout software is selected according to the intended electric product to be realized. If you are a beginner, it is important to know that there are various types of layout software available. Here are 6 of the most common ones:
EAGLE (Easily Applicable Graphic Layout Editor)
A free PCB layout software that can be download on Windows, Mac, and Linux. It is largely popular because it is easy to use and has a vast library of electronic and electrical components. Using the software’s schematic editor, the designer can add the components and link them according to circuit requirements. The schematic is converted to PCB layout editor to set components in place.
Multism is common among layout software researchers and trainees because of its history. It was developed to teach electronics in colleges and offers teaching, research, and design solutions. These features render it an optimum option when it comes to PCB design for beginners.
Among its key strengths is its capacity to analyses both analog and digital electronics. Besides, it also allows integration with complex parameter analysis, embedded targets as well as simplified design with templates that the user can define to suit the purpose.
Often given equal credit with EAGLE but also thought to surpass it because of its excellent simulation environment, even though EAGLE has a superior offer for PCB layout design. Multisim can be downloaded on Windows.
OrCAD is also downloadable on Windows, Linux, and Mac. The name of the software is derived from the company name (Oregon) and CAD (Computer-Aided Design). The software has a standard OrCAD design suite, OrCAD Professional, and Allegro suite.
The Standard suite is used for concepts on the production design while the Professional suite offers design skills. The Allegro suite is used by professionals at the expert level.
Altium can be downloaded on Windows but using the software digs deeper into your pocket compared to most of the other layout software. Annual subscription ranges around 7000 dollars. However, its advanced features for PCB design makes it worth the coin. They include designing, development, field-programmable gate array, and schematic capture.
Altium can produce the most complex designs in a short time and with ease, which makes it perfect for BCP design for beginners. Designers can have a 3D preview of their work to notice and check the smallest details on the design.
Originally developed by Jean-Pierre Charras, KiCAD is a free electrical design software under the creative commons (CC) License. It can be used to create 2D and 3D PCB layouts among other features. It has a library useful for PCB design for beginners.
PCB designers find KiCAD’s schematic editor and layout viewer most useful for creating and modifying the designs. The software supports files created with EAGLE.
A web-based option for automated electronic design. This means that you log into the company website and work from there without needing to download and take up space on your machine. It is described as an easy to use interface which makes it a good platform in PCB design for beginners. When using EasyEDA, you have the possibility of consulting a wide range of projects from the library.
The greatest strength of Easy EDA is its capacity to support PCB schematic and libraries from Altium and EAGLE plus a few other design software not discussed here.
Steps in designing PCBs
With the foregoing knowledge on PCB, it is easier to understand the steps used in designing PCBs. We outline the major steps in PCB design using the Altium software described above.
Step 1: Creating the schematic
In PCB design, converting a schematic to a board layout is always the easier choice. It is more arduous to design directly on board. The schematic may be a template or one created by the designer and is used to create and edit the layout.
Step 2: Creating the board design
This entails producing a blank PCB document (PCBdoc) using the software. The doc allows you to set the design shape and dimensions. You can review and update the options before creating the final PCBdoc.
Step 3: Linking the schematic to the board
This involves linking the schematic information to the PCBdoc using these steps on your layout software.
- Click on design then update PCB (name of your PCBdoc)
- A dialogue box opens that allows you to view the components from the schematic. You then verify the changes by adding the schematic information to your PCB project correctly and clicking on the validate changes option once you are done.
- A green status on all items indicates a go ahead and you can confidently execute the changes.
- Close the dialogue box.
Step 4: Defining the Board and layer stack
Using the layer stackup manager on your software, you can define the shape and number of layers for your PCB.
Step 5: Placing the components
On Altium designer, you can opt to place the components of your circuit automatically or manually. Combining the two options may allow you to verify that each component is placed in its respective place.
Step 6: Mark the drill holes
This entails inserting the marks on the spots where the drill holes will be made on the actual board. Some designers may describe it as mounting and vias. The holes should be drilled according to the specifications of the PCB manufacturer.
Step 7: Routing the traces
Routing entails creating connections between the components. If you have more than one layer on the actual board, routing is done through holes from one layer that serves as a ground plane through all the layers to the one that acts as the power plane.
Step 8: Verifying the circuit layout
On the PCB rules and constrains editor, you run the design rule check on your software by clicking on those rules that apply for your design.
Step 9: Adding the legend
When all the above has been done, it is now time to add the labels, markings, logo, identifiers, and other aspects of the silkscreen. Ensure that the font is easily readable by the user.
Step 10: Generating the design files
The design files are generated as Gerber files. Gerber files are the standard format for PCB presenting as a photoplotter for building the actual board.
The comprehensive process for PCB designing can sound complex for beginners. Mastering the basic terms, knowing the available software and the strengths of each, and following the simple steps outlined can make PCB design for beginners much less complicated.