In this KiCad tutorial, we will explain how to create a schematic and a symbol library for components to be used in the schematic.
But before, that let’s have a brief look at the KiCad component library.
Component library in KiCad
All the components used in a schematic are described in the component libraries. Several libraries are used to provide reasonably simple component management, through the grouping of components by its subject (by functions, manufacturers).
The component library contains a large variety of preinstalled libraries. Also, the Library Manager menu helps you to modify libraries like: build new libraries, add and delete components from libraries, and pass a component from one library to another.
Check out the KiCad library for symbols before creating your own: https://kicad.github.io/symbols/
Creating a schematic and symbol library in KiCad
If you just downloaded KiCad, you might have to install some libraries, like schematic and symbol libraries. Today, we are going to show you how to proceed.
First, let’s open KiCad on your computer.
In order to create a new project, follow these simple steps:
- Go to File on the left-hand side
- Click New
- Select Project
You can select the respective location where you want to save this new file and name it. For this demonstration, we will call it New Design. You can now click Save.
Once your new project is created, it opens automatically and you can see two files. One is the board file and the other one is the schematic file, which we created already.
How to create a schematic in KiCad
To create a new KiCad schematic, double-click on Schematic. We need a schematic design which we will draw over the appearing frame. If the schematic design is available, you will find certain components, such as capacitors, inductors, or maybe simple ICs, like regulators on the right-hand side. Click a symbol and drag it to the center of the frame.
Double click on Schematic > select a pre-installed library/click create to add a new KiCad symbol
All the libraries will load and a window will pop up. These are pre-installed libraries and symbols which already exist in KiCad. For instance, we can click this schematic symbol and place it in the frame.
If a symbol is not available, you can create a new KiCad symbol by clicking Create, delete, or edit symbol at the top.
How to create a new library in KiCad
But before creating a symbol you need to create a new KiCad library. All the libraries you can see on the left-hand side are in-built libraries so you won’t be able to modify them.
To create a new library, on the left-hand side, under File, click New Library. You have to browse to the location where you want to save it and name it.
You now have two options: Global or Project.
Basically, if you are using this library specifically for your current project, you can select Project. If you select Global, this library will be added in the predefined libraries which already exist in KiCad. For this demo, we will select the global one. Now the library is created.
How to create a symbol in KiCad
To create a new KiCad symbol, follow these simple steps:
- Go to File
- Click New Symbol
- Select the library in which you want to save the symbol
This window will pop up where you can name your symbol, for instance, IC and click Ok.
You can now see IC, which is the name of your symbol, and U, which is the reference.
Select the reference and move it from the center. Repeat the same action with IC.
Let’s zoom out of it.
To set the grid, right-click on the screen and you will see an option called Grid. It’s best to keep it to 50 mils.
Let’s say you want to create a symbol for IC. On the right-hand side, click the rectangle called Add graphic rectangle to symbol body. Select it and draw a box.
Before connecting the pins, which are nothing but the terminals of your IC, you need to fill the background of this box. There are two different ways to do this:
- Place your cursor on this line > right-click on it > select Edit Rectangle Options > select Fill with body background color. It will color the entire shape.
- Another way to complete this action is to keep the cursor on your line and click E on your keyboard. The Rectangle Drawing Properties window will appear and you can directly select Fill with body background.
How to place the pins
You now need to place the pins. On the right-hand side, click the A1 symbol. Then, you can drag it and click the screen.
Click on A1 symbol from right toolbar > Configure your pin properties
The Pin Properties window will pop up. You can now configure your pin properties.
Let’s pretend this as a regulator. A regulator has basically three pins which are input, output and ground. Therefore, we will require three different pins.
Fill out the pin name and the pin number fields. Here, we will write IN and 1. You can personalize the other properties.
Let’s say you want to rotate and place this pin on the left-hand side. Right-click on your screen and select Rotate Clockwise.
Repeat the same action for the two other pins.
The second pin name will be GND and the pin number 2. As for the electrical type, you have the option to choose Unspecified. Click on the screen, select Rotate Clockwise, and place this pin over here.
The last one is output. The pin name will be OUT and the pin number 3.
In the video tutorial, we have used three pins with name Input, Output and Unspecified, and connected to the bottom of the device. If you want to add more pins, you can add on all sides of the rectangular box.
Once the pins are placed, right-click on the screen > select End Tool.
You can see the pins are placed and the names are given. The symbol is completed. You can save it. Remember this library name, which is New Library 0 here, and the symbol name, which is IC here, as you can see at the left-hand bottom corner.
How to use the symbol in the schematic
Once you save the symbol, you can minimize your window. To use the symbol in your schematic:
Open your schematic page > select Place symbol on the right side from the toolbar > Drag it to the center of the screen > Choose Symbol window will pop up
From Choose Symbol window search for your library. Here, it’s the New Library 01. You can see the preview of the symbol IC we just created. Place it on the schematic, right-click, select End Tool and Save.
This is how we create a schematic and symbol library in KiCad.
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