It seems to me that a lot of beginners want rules that, if followed, guarantee their design won't fail. But I don't think that there are such things. I like to think of it as: you pick and choose how and where you want your system to fail, and how much time, effort and money you want to spend mitigating these sources of failure. As your expertise grows, you will start using your knowledge in integrated, holistic ways that cannot be captured in rules, and you too will probably one day experience the frustration of trying to answer a beginner's questions by "back-forming" a set of rules that would have produced the right answer in those particular circumstances. (Just to leave no doubt: I am nowhere near this high level in hardware, though I am in certain areas of software.)
That's a brilliant article. I crack up every time I read, "Some people worry that conduction electrons are traveling so fast that they won't be able to make it around a square corner. Perhaps they might reflect back or fly off into space."
(I imagine that certain types of audiophiles have special paint that they can put over circuit board traces that would help reflect back into the traces any electrons that might fly off them. This might relieve a certain "hollowness" in the upper mids. But only a thin layer of paint must be used lest phase coherence be reduced!)
"Copper pours" (or fills) do
not qualify as a ground plane. Not at all. I give a diagram at
viewtopic.php?p=55094#p55094 showing what goes on, with a mechanical analogy. A signal's ground return current must run very close to the signal line, without interruptions. Copper pours will have interruptions.
I read something really good, here or elsewhere, about ground return following the signal path and how power and ground planes work, and I felt that really helped me get what was going on. Maybe it was a combination of posts and that's why I can't point to just one.
But anyway, if I understand it all correctly, the real advice is not that fills are useless, but: "You can't assume that just pouring some fills will help anything at all." But fills can be useful, as opposed to not having them, if you have conductors on the other side running across the fills where going across the fills would be a preferred route for return current, right? And in those cases it's not the fill
per se being useful there, but just the parallel current path, and just doing a ground return trace following the current trace on the other side would do just as well, right?
