Am I missing a library?


#1

Noob here. I am trying to add a 2N2222A transistor and it is not in the symbol library that comes with 5.0. While I can figure out how to create a custom component and library, this seems like a super common generic transistor. So, before I go through unnecessary work doing that, is there a kicad library available that I can download and use (for all projects)?


#2

Use the 2N3904.
You can duplicate it in the library and rename it to the 2N2222A.


#3

Thanks. I’ll see if I can figure out how to do that. Question: Should this cloned device go into the system library or should I create a custom library (guessing the latter). And if using a custom library, is there a way to have this new library available to all projects by default, or do I need to add the custom library to each project?


#4

Add the 2N3094 to a schematic.
Hover the mouse cursor over the part and depress “Ctrl + e” on the keyboard.
Right click on the device in the left pane and select “Duplicate Symbol”.
Double click on the duplicated device name in the left pane.
Change the name of the part from 2N3904 to 2N2222A.
Save.

It is a good idea to use custom libraries; as otherwise when KiCad libraries change some symbols/footprints may be changed/removed in the future.

I personally have custom libraries available to all projects by default, however it is also possible to have project specific libraries. It seems that the optimal solution could be based upon a user case by case basis.


#5

The 2N2222A was a TO-18 part, it is best to make your own symbol and set the footprint filter for TO-18.
As most TO-18 devices out there are old stock and often fakes, you might be planning to use the more available PN2222A, which is a CBE TO-92


#6

@davidsrsb Good additional information added to the thread.

However!

I guess it is my advancing age that makes me wonder about some of the details with these sorts of things. I’ve seen many 2N parts that appear they would work just fine with the TO-92 footprint. And, to add a little more confusion to the mix, check out the TO-92 hand-soldering footprint in KiCad!


#7

All depends on using TO-92 spread leads Vs inline footprints. PN Vs 2N part also affects 3D view and clearances. The TO-18 can is connected to the collector, so you have to be careful about it touching something


#8

@davidsrsb I’m now fairly certain that my misunderstanding was a result of my prior life experiences.

I dug out a board from 1986 that I thought had 2N2222A transistors… and they are actually 2N4124 parts. And, they have 2N2222 normal footprint spacings; there is no silkscreen, but that is not uncommon for the type of board of that era.

It well may be that in all the times I ordered a replacement 2N2222A, that the PN2222A, 2N4124, or 2N3904, was considered a “suitable sub”; as they all have bendable leads.

Interesting to me!