Draw Electronic Schematics with CadSoft EAGLE

There are a couple instructables here on some of the finer points of Eagle (making your
own library parts:
modifying the design rules: )
But feedback indicates that a lot of people could probably use an instructable on the
more basic aspects of creating a schematic and board.

This instructable covers creating a schematic, presumably from a printed schematic in
a magazine or image on the web. I'll start with schematic shown, which is from
It's got a "typical" collection of parts, and is vaguely useful as well.

Cadsoft EAGLE generic information:

Cadsoft EAGLE is available from

Cadsoft is a German company that is a veritable mecca of software distribution enlightenment. In addition to the reasonably-priced professional PCB design packages ($1200), they have freeware, lite, non-profit, and other intermediate licenses. Their software runs under windows, linux, and MacOSX. It's slightly quirky, with a steep (but not too high) learning curve on the front end, but from most reports it is not any more so than other professional CAD packages. They have online support forums that are active from both the company and other users, the package is under current development and gets better with each release. A number of PCB fabricators will accept their CAD files directly. It's good stuff.
Use it. Propagate it. Buy it when you "go pro."

See also:
Creating PCB from Schematic
Creating Library parts
Design rule modification
Send CAD Files to manufacturers

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Step 1: Create new project

Start up the Eagle control panel, and right-click on "projects" to create a new project.
You'll get to name it whatever you want.

Step 2: Create new schematic in the project

Picture of Create new schematic in the project
Once you have cretaed the new project, it will be "opened" automatically (which doesn't do much other than tell EAGLE that "this is the current project".) RIght click on the new project and follow the popup menus to create a new schematic.
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stainsor6 years ago
DO NOT click the "Drop" button in the Add dialog. My first time using Eagle I thought that was the button to drop a part into a schematic. It turns out that's the button to remove a set of parts from the libraries! If you do click this button and accidentally remove some of the libraries you can get them back by reinstalling Eagle.

If I knew anything about UI design (which I don't) then I would probably say that this was a horrible choice for both the placement and naming of the button. I would probably think that it should be changed immediately.
RobT3 stainsor3 months ago

Ha! Just did exactly the same thing, going to "Drop" my first part onto the schematic...

Very strange name for a button - why not try, "remove from list"!?!!!

rachel stainsor6 years ago
Ha! I was just about to add this same comment, as I had the exact same wrong thought about what "DROP" meant. It's a terrible design choice and doesn't even have a confirmation dialog! Danger Will Robinson!
Looks like you can get the library back by clicking on library/use, then select the library you want
Fik joie2vivre2 years ago
I own you a coffee... I dropped the very first library I touched ever, and was about to download the installer again. After reading your comment, I went to Library>Use instead. Doesn't say anything in the help, either.
 haha i pressed that aswell, but never figured out what it did xD
It's very misleading, but all you've actually done is "disable" that particular library. The Control Panel window that opens on startup allows you to re-enable that library. Just expand the "Libraries" and click the dot beside the library you disabled.
THANK YOU. You wouldn't believe how hard it was to find an answer (at least one I could figure out how ).
WHEW!!! Thanks Bud... You just saved me hours of grief.
Thank you webster32
Thank you. I did the same thing as Stainsor. :)
That's also what I initially thought, I tried it on a random weird component by curiosity.. It doesn't warn you, there is no tool-tip.
AMS India11 months ago

Awesome Tutorial! I really appreciate you for sharing such a useful information for the starters through diagrams.

Thanks and regards

AMS India

kooth1 year ago

I have just decided to try Eagle and I'd like to say that your Instructable is very helpful! Thanks so much for posting this. Your Instructable is still relevant!


Keith E. Cooper

Where is the power to your circuit?
audioindo2 years ago
Thanks alot for the Resistor code explanation, I also looking for this one.
So R-EU basically same with R-US right?
R-EU_0204/7 means 1/8W resistor with 7mm spacing?
How about capacitor? like 3n3 C-7-10/5
donfrench2 years ago
Thanks a lot for the resistor coding info. I did a lot of unproductive searching before I found this page.
omnibot3 years ago
"You might think that you'd use the "wire" command to make connections in your circuit."

-Why yes, that's exactly what I thought and apparently why it's NEVER worked before for 2 years of trying. You'd think they'd something like that on the first page in the manual. I am so angry right now.
dav3id3 years ago
Thanks, Had used Eagle several years ago but this really helped quickly figure out a couple of things that could have taken a lot longer before I got going, it was a great starting point / refresher for this new project.
SharpyWarpy3 years ago
Okay I clicked on the "Display" button and made visible only Bottom, Pads, Vias, Holes and centerDrill layers. Clicked "Tools > Ratsnest" to bring up the ground plane. I clicked on File > Print. Then in the dialog box part "Printer:" I chose "Print to File (Postscript)" and also in the "Options" I checked the "Black" box. I changed the "Paper" option to "Letter", which might not have really been necessary. I made sure "Scale" was set to one and then changed the save directory to my home directory and clicked "OK". I opened a postscript viewer -- in my case "Evince" and opened the file and printed. The drill holes were there. I'm happy.
SharpyWarpy3 years ago
I have a problem when I create a board from the schematic. I move all the parts relative to the schematic as directed in this tutorial but when I generate the board the wires go right into the holes! And I can't get them to back up. So when I etch the board I'm not going to have holes in the copper where they need to be. The only thing I can do is delete the wires one at a time and draw them each by hand stopping the ends just short of the holes in the pads or vias. But then after that I lose the annotation between schematic and board. Is there a design rule I can use to fix this? I made my own design rule configuration file but I didn't see anything in there about this problem. What can I do? Thank you all ahead of time.
westfw (author)  SharpyWarpy3 years ago
When printing, the "holes" are normally done last, punching through whatever traces may show on the display as going all the way to the center. In fact, normally I use the "drill-aid" ULP to reduce the size of the holes to "pilot hole" rather than full sized. It's also the case for CAM output in formats that support holes (eg Postscript) Don't be fooled by the preview that shows up in the print dialog.
Thank you, westfw for your reply. After I posted I did a bit more searching and discovered the "drill-aid.ulp", tried that and thought it was not working because it doesn't show up but if I understand you correctly it will show up on the printout? So should I save the layout in monochrome and postscript format for printing?
SharpyWarpy3 years ago
Interesting you used one of Bill Bowden's circuits. He's one of my favourites from which to learn. He's very approachable and very nice. I've built 6 or 7 of his circuits and they always work fine. Great Instructable, I appreciate the time and effort you put into ALL your Instructables. Your effort is not wasted.
mspinks3 years ago
I can't believe I was using the wire command this whole time! This is so much faster! Thank you!
Thank you for all your effort putting this instructable together. I had been complete lost as to how to drive eagle until I read your excellent work.
Rue Dee3 years ago
Never-mind, i have just realized the mistake i was making..
Rue Dee3 years ago
Thanx for the drop button issue, i did the same.. i'm trying to add a 6 pin molex connector. But when i select it and click ok nothing happens, what should i do?
spsj213 years ago
it is really a nice instructable. So far I was struggling for a nice EAGLE tutorial and finally it helped me a lot.
tcarney573 years ago
I'm just now giving Eagle a try. Thanks for the introduction. Already I'm not surprised this is a foreign (German) program--I think some of the words and labels are poorly translated. Like Stainsor, I would have assumed drop meant to place the part on the schematic. It seems to me that "remove" or "delete" would have been better. But to use "drop," as in "drop like a hot potato," or "drop the course" doesn't work in this context.

Likewise, why is the word "smash" being used for a function that "[s]eparates text variables and attributes from parts or elements." And what does "separate" mean in this context? That the variable or attribute labels can be moved to a different spot around the part symbol as needed to make the drawing more readable. Wouldn't "rearrange labels" or even "detach" be better in the help-file description than "separates."

After I learn and grouse about these little quirks a while, I think Eagle will be very useful, especially since it seems to be a quasi-standard in the low-end (or free) market.
badbad2144 years ago
Thank you!
Russ12344 years ago
You have 2 diodes on Q2. Thanks for these tutorials.
westfw (author)  Russ12344 years ago
There's an explanation for the two diodes with the original schematic here:
Basically, the 555 is not "rail to rail" on its output, and otherwise would not be sure to turn off the "upper" transistor when in the high state.
mauselous4 years ago
Thank you so much for the helpful tutorial. The steps you illustrated really helped me get a handle on getting from circuit to schematic to layout.

Do you have any tips on where to find additional or alternate libraries that are more organized?
westfw (author)  mauselous4 years ago
The EAGLE user community forums are active and helpful, and frequently people will share libraries for newer parts.

I don't know about "more organized", though. I haven't seen any organized attempt to modernize/fix/organize a comprehensive set of component libraries for EAGLE, but it's likely that such a thing would be in the "costs money" realm where I wouldn't notice.)

(there is the recent Element14/Newark/Farnell effort to tie EAGLE directly to parts purchases; I haven't paid much attention to that since they're not one of my preferred dealers.)
Cobalt594 years ago
Where to find a + to GND power supply in the ADD dialog?
mrmizuno14 years ago
Thank you. very helpful.
coryjrogers4 years ago
"your mouse pointer BECOMES your drawing tool"
westfw (author)  coryjrogers4 years ago
if you insist!
ihart4 years ago
Thanks for doing this. Now I need to check out your PCB instructable.
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