So I’m really new to electronics, so maybe this is just me being a noob… But the footprints that I pull up from the readily available KiCad library, sure don’t look right. For example, the Arduino UNO R3. Now, I’m not planning to use this, but I wanted to use it as a point of reference. I am no expert on electronics drawings, but this sure doesn’t look like a one-to-one representation of the hardware that is in front of me.
I’ve seen several like this. I’m assuming that I’m to be able to use these footprints to mark a PCB. It would be super nice, then, if everything was where it was supposed to be. If there’s a secret to reading this a different way, please clue me in. I’m lost.
The generic is fine for the schematic symbol. You then choose a footprint to go with it. I see JST in the footprint editor as a selection. I think the Dupont are pin headers. You just need to know the spacing.
Remember, this is a footprint to be paired with the symbol. Something like a 2 pin connector can have dozens of footprints that could be associated with it. What OS are you using? It could be a packaging problem. Shouldn’t be though. I think everyone just uses the libraries ‘as is’ provided by the Kicad team.
One quirk as I recall is you have to add libraries ‘per project’. It speeds us caching if you don’t use them all and no one needs them all. For hacks like me that don’t know stuff that well I just load them all.
The only thing I really came across was a component marked as 0603 that in fact turned out to be twice the size of an 0603. No big deal in this case, easily solved.
Updated footprints are all available online and the sole reason I use Kicad is the fact that it supports these imports. Default libraries are great to get going but Im not sure how far I’d trust their up-to-dateness. Issues on lesser used parts would not likely be spotted or resolved.
The default footprint associated with a Schematic Symbol is just one of many available. It is often the case that slight variations occur between manufacturers and older parts tend to be available from more than one manufacturer (usually JEDEC compatible stuff).
Where there are many footprints available on the same part, same manufacturer, the difference is here a slight variation in the size of the pads. These are normally in the flavours of Normal, Most and Least. You see this on Ultralibrarian a lot.
Footprints may not necessarily fit exactly the legs, pads etc of the devices. They are usually larger and require masking with the Solder Mask Paint step. This affords a tolerance during the soldering step.