Modify Existing Symbol


#1

Is there way how to take existing symbol from kicad library modify it and save it in my own library?


#2

Assuming you run version 5.

The “Example with separate power units” of this tutorial handles that: Tutorial: How to make a symbol (from scratch)


#3

Yes Kicad 5. If I do it like it is demonstrated in this tutorial … I need to draw transistor KSA992 so I choose PNP transistor BC557 as reference symbol. I copy it then I paste it into my library folder and it pasted another 7 transistors(probably all using same symbol) when I want to delete the unwanted ones it deletes all of them.


#4

Ah. You are experiencing the surprise of symbol aliases. Look carefully at what copies over and you will notice that all but 1 symbol name are italicized. The italics indicates an alias. Symbol aliases allow for (within the same library) using the same graphical asset for multiple parts.

Once you’ve copied your desired symbol (and all the alias), open the symbol in the library editor. (Make sure you open the copied symbol. I don’t know how many times I’ve had to redo edits because I didn’t notice that the currently editable symbol was the original in the write-protected installed libraries.) Edit the symbol properties and you should find a list of symbol names in the Aliases tab. Here is a screen shot of what I have for the BC557:
2018-12-05%2009_57_33-Properties%20for%20BC557

Alternately, you could just insert the generic PNP transistor (Q_PNP_CBE for this pinout) from the Device library into your schematic and change the value to KSA992. Unless you need ordering information as part of your libraries…


#5

I think i should update my tutorial then to use a symbol that has aliases as the basis. This really seems to trip up people.

Well i am not surprised to be honest. The symbol vs alias stuff could really use some better communication in the tree view. maybe putting the aliases below the symbol (as another layer) could be an option.


#6

I like that idea. Either simply indented, or collapsible like a directory tree.