# Finding Eagle libraries

#### MrSoftware

Joined Oct 29, 2013
2,015
I'm getting started with Eagle and I'm having a devil of a time finding libraries for some of the parts that I want to use, at the moment it's st-micro MOSFETs such as part# STD35NF06LT4. So my question is, for you guys who use Eagle, is it standard that you have to take time to create your own devices inside Eagle the first time you use them, or are you typically able to find existing libraries and library hunting is just a skill that I need to further develop?

#### jpanhalt

Joined Jan 18, 2008
11,088
Most passive parts are in the libraries. For active components like a specific mosfet, if it is not in a library, I use a generic with the same package. Remember that only the number of pins and package really matter. The symbols could in theory all be blank.

Here is an example:

You can use the value tool to change the "name" and ignore the warning or make an identical part with the new name/value.

John

#### mcgyvr

Joined Oct 15, 2009
5,394
Simply learn to create your own..

#### SLK001

Joined Nov 29, 2011
1,548
I have created most of my parts. Once you do a couple of parts, you'll find it easier to make your own rather than embark on a search for premade libraries. I have a library named "1-PARTS.LBR" where I keep the parts that I have built.

#### nerdegutta

Joined Dec 15, 2009
2,681
I use Google 2-3 times, with different searchphrases. If nothing comes up, I make the part.

#### mcgyvr

Joined Oct 15, 2009
5,394
I always make my own..
I NEVER trust a library I didn't create..
A simple mistake in a library can cost thousands of dollars..

#### JohnInTX

Joined Jun 26, 2012
4,443
I always make my own..
I NEVER trust a library I didn't create..
A simple mistake in a library can cost thousands of dollars..
+1 And there are some mistakes in there.
You can usually find something similar enough to serve as a starting point. I created my own library folder with subfolders of parts (R's, C's, LED's microC's and especially connectors) that I've used. That way, I don't have to search through a gazillion parts to find something that I might not be able to find in stock at a distributor. I put the full manufacturer's P/N and order codes for Mouser and Digikey in the description box. Eventually, you wind up with a bunch of parts that you can drag to the schematic and actually order (or already have in stock). I also detail the PCB pattern for consistent hole sizes, nomenclature style etc.

#### jpanhalt

Joined Jan 18, 2008
11,088
I agree in principle with mcgyvr's comments.

I tend to make my own Devices (package + symbol) unless it is in Eagle. I will use Eagle's libraries routinely, but always check the package of SMD devices, unless I am sure it is a standard. There are definite manufacturer differences. I will also rearrange a symbol to my liking.

I do not trust user submitted libraries on the Eagle site. Some are good; others are not. So, on the occasion that I have used such a library, I always check it thoroughly. Sometimes, you find some real "make do" errors. Symbols are so easy to make, I am more likely to draw a symbol from scratch than a package. For packages, if I find a good one, I will modify it, rather than make it from scratch.

When dimensions are critical, like for a PCB outline that needs to fit in a particular area or a tiny connector with alignment pins, I will often draw them in a typical 2D CAD program, export as DXF, and import into Eagle using a DXF import ULP (I am still on Eagle 7.2 ). I import as one layer and then trace or change layers as needed. I also align to the same origin as is used for everything else in the PCB. That can be done accurately using either a command line or the "information" icon and gui .