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1. What is PCB
Before we get into the difference between PCB schematic and design, we need to understand what is PCB?
Inside electronic devices, there is basically a printed circuit board, also known as a printed circuit board. This green circuit board made of precious metals connects all the electrical components of the device and enables it to function properly. Without PCB, electronic devices will not work.
2. PCB schematic and PCB Design
The PCB schematic is a simple two-dimensional circuit design that shows the functions and connectivity between different components. PCB design is a three-dimensional layout that marks the location of components after ensuring the normal operation of the circuit.
Therefore, the PCB schematic is the first part of designing a printed circuit board. It is a graphical representation, whether in written form or in data form, that uses agreed-upon symbols to describe circuit connections. It also suggests the components that will be used and how they are connected.
As the name suggests, the PCB schematic is a plan, a blueprint. It does not explain where the components will be specifically placed. Instead, the schematic lists how the PCB will eventually achieve connectivity and forms a key part of the planning process.
Once the blueprint is completed, the next step is PCB design. Design is the layout or physical representation of the PCB schematic, including the placement of copper traces and holes. The PCB design shows where the above components are located, and how they are connected with copper.
PCB design is the stage that is concerned with performance. Engineers build real components based on the PCB design, allowing them to test whether the device is working properly. Earlier we mentioned that anyone should be able to understand the PCB schematic, but its function cannot be easily understood by looking at a prototype.
Once both stages are completed and you are satisfied with the performance of the PCB, it needs to be realized through a manufacturer.
PCB Schematic
3. PCB Schematic Elements
Now that we have a general idea of the difference between the two, let's take a closer look at the elements of a PCB schematic. As we mentioned, all connections are visible, but there are a few things to keep in mind:
In order to be able to see the connections clearly, they are not created to scale; on the PCB design, they may be very close to each other
Some connections may cross each other, which is not practically possible
Some connections may be on opposite sides of the layout, with markings indicating that they are linked
This PCB "blueprint" can depict everything that needs to be included in the design in one, two, or even several pages
One final note is that more complex schematics can be grouped by function to improve readability. Arranging the connections in this way will not happen in the next stage, and the schematic will usually not match the final design of the 3D model.
4. PCB Design Elements
Now it's time to take a deeper look at the elements of the PCB design file. At this stage, we transition from a written blueprint to a physical representation constructed using laminate or ceramic materials. Some more complex applications require the use of flexible PCBs when particularly compact spaces are required.
The content of the PCB design file follows the blueprint laid out by the schematic process, but, as mentioned before, the two are very different in appearance. We have already discussed the PCB schematic, but what differences can be observed in the design file?
When we talk about PCB design files, we are talking about a 3D model that includes the printed circuit board and the design file. They can be single-layer or multi-layer, although two layers are the most common. We can observe some differences between the PCB schematic and the PCB design file:
PCB Design
All components are correctly sized and positioned correctly
If two points should not be connected, a detour or switch to another PCB layer must be made to avoid crossing each other on the same layer
Also, as we briefly touched on, PCB design is more concerned with actual performance, as this is somewhat of a validation phase for the final product. At this point, the practicality of the design having to actually work comes into play, and the physical requirements of the printed circuit board must be considered. Some of these include:
How the spacing of the components allows for adequate heat distribution Where are the connectors on the edge?
How thick must the various traces be in regards to current and heat issues
Since physical limitations and requirements mean that the PCB design file often looks very different from the design on the schematic, the design file includes the silkscreen layer. This silkscreen layer indicates letters, numbers, and symbols to help engineers assemble and use the board.
It is required that after all components are assembled on the printed circuit board, it can work as planned. If not, it needs to be redrawn.
Although PCB schematics and PCB design files are often confused, in fact, making PCB schematics and PCB design refer to two independent processes when creating printed circuit boards. A PCB schematic that can draw the process flow must be created before PCB design can be carried out, and PCB design is an important part of determining the performance and integrity of the PCB.