So I'm using EAGLE for the first time, and I have zero experience with any EDA software. I've completed a schematic and would like to proceed to design the board layout, but I am stalled by these warnings which make zero sense to me.

Whenever I add and connect a power supply element I get these warnings. I'm not sure why, and thus far I have seen people saying that this is a stupid side-effect of how EAGLE handles its nets. So the question is; are these warnings something to be taken care of in some way (if so, how?), or should I simply ignore/approve them? Please advise.

Bonus question; I know a bit about electronic circuitry, but I am not an electrical engineer. Do you have any tips and tricks that I just be aware of in large PCB designs? I.e. I have added decoupling capacitors of 0.1uF across any and all IC power supplies. Are there more things like this to take into consideration? Any information is welcome and helpful :)

enter image description here

  • \$\begingroup\$ In kicad we have a "power flag". Maybe there's something similare in eagle. Or you can always switch to kicad, which is free and WAY ahead of eagle \$\endgroup\$ Commented Sep 21, 2018 at 13:44
  • \$\begingroup\$ Hi there! I don't see any options for the particular power supply elements. I'll try and research further on your input — seems logical, although one would expect a power supply element would default to such a flag. I tried Kicad, but I couldn't get it to do anything and it kept crashing on me. So after about 10 minutes it was scrapped. I've also tried EasyEDA, but I'm reluctant to use online tools for something that might be worth selling. \$\endgroup\$ Commented Sep 21, 2018 at 19:20
  • \$\begingroup\$ Include a shot of your schematic if it's not secret or proprietary, as it may make obvious if you have parts that require additional schematic components or some such. Some of the errors seem to imply that you have cross connected nets somehow without combining them. \$\endgroup\$
    – K H
    Commented Sep 22, 2018 at 1:49
  • \$\begingroup\$ It's a rather large schematic with several modules, and also yes, I'd like it to stay a secret, for now at least. Perhaps it is due to the modules? In each module I've simply put new 5V and GND where ever needed. Do I need to bridge the net through the module, or does EAGLE know that these are one and the same net? \$\endgroup\$ Commented Sep 22, 2018 at 5:33

2 Answers 2


On the schematic, make grab each device and drag it a little to make sure all pins are actually connected. That should help you find things like IC1P V+ connected to N$2 vs being connected to 5V.

Check the board layouts, make sure the pins you think are connected to 5V are actually connected to 5V. I change the Unrouted layer to something more easily seen - like Yellow when the Top & Bottom layers are turned on, or Black when they are not - to see them more easily. Run the Rats Nest to make sure there are no airwires. If all the pins are connected as you want, then you can Approve or Ignore the warnings.

I add a Ground layer to both top & bottom. Draw a Polygon around the outside of your board, and Name it Gnd, for both layers. May have to tweak the end point of the polygon a little to not have it overlap itself. Do not route Gnd signals - let them connect to the Gnd plane. Maybe just add a short section of Gnd trace to an SMD pad if it is a thin pad and will connect automatically. Add Vias Named Gnd to connect the top & bottom layers. Companies like iteadstudio.com will accept vias as small as 12mil to connect the layers. I may go that small near an SMD pin to connect it to Gnd on the bottom layer. Then use 20 mil or 24 mil vias to connect the layers. Rats Nest will make the layers show up. You can use the Rip Up button to make them hidden again.

  • \$\begingroup\$ Hi there! I've tried to wiggle the components around, but the warnings remain. The particular warning you are referring to is indeed meant to connect to N$2, as that net is controlled by a relay, which may or may not have 5V attached. This is to save power. As far as I can see the warnings are triggered by connecting the supplies to the IC's, not that they aren't connected. Great tips on checking from the board as well — I'll give it a go tomorrow, thanks! \$\endgroup\$ Commented Sep 21, 2018 at 19:37

I didn't find any solution to the warnings, but I checked out the PCB board and it seems as though both 5V and GND are correctly connected. I guess EAGLE is just being pedantic about detail that I don't know about :)


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.