Board layout question

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I was just perusing the forums and read this post: https://www.avrfreaks.net/forum/s...

 

and had a question about the portion circled in red. Is there a reason why you would not just leave the conductor around the pad? Or even just the lower-right-hand semi-circle?

 

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Last Edited: Wed. Mar 23, 2016 - 09:45 PM
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That is called "thermal relief". It is used with soldered pads to keep the soldering heat from flowing away too rapidly, thus making solder connections difficult. 

 

In this case, the layout software must have decided that its a pad, so add thermal relief, even though there is no intended solder. But, of course, the software does not know that it will never be soldered.

 

Jim

 

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That makes sense, thanks!

  • "Give me six hours to chop down a tree and I will spend the first four sharpening the axe."  -- Abraham Lincoln
  • "All right wise guy, where am I?"   -- Daffy Duck
  • "Well, we're safe for now. Thank goodness we're in a bowling alley."  -- Big Bob, Pleasantville
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Some further examples

 

 

Last Edited: Sun. Mar 27, 2016 - 08:19 PM
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hehe

 

That's my photo from long ago. I wonder why I made 90 degree corners in all those traces.

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Because you didn't know any better. :-)

Leon Heller G1HSM

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Torby wrote:
hehe   That's my photo from long ago. I wonder why I made 90 degree corners in all those traces.

 

What are the advantages / disadvantages to this? They look very neat and tidy...

  • "Give me six hours to chop down a tree and I will spend the first four sharpening the axe."  -- Abraham Lincoln
  • "All right wise guy, where am I?"   -- Daffy Duck
  • "Well, we're safe for now. Thank goodness we're in a bowling alley."  -- Big Bob, Pleasantville
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With narrow tracks and close spacing there is a danger of under etching causing shorts.

Leon Heller G1HSM

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Etching tends not to work so well in 90 degree corners. Even less well in acute corners. That is one of the reasons why "chamfered" corners are often used. Good layout avoids sharp corners.

 

Jim

 

Until Black Lives Matter, we do not have "All Lives Matter"!

 

 

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I'm in no way a PCB expert but isn't there also some thing with sharp corners and HF signals?

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JohanEkdahl wrote:
I'm in no way a PCB expert but isn't there also some thing with sharp corners and HF signals?

 

Found this: 

 

http://electronics.stackexchange...

 

and this:

 

http://www.sigcon.com/Pubs/edn/b...

 

 

Apologies that this is not a cut-and-dried question, I am not well enough versed to have the ability to formulate such questions at this time, but through the discussions I am better learning what to ask, and how to structure Interweb queries to improve my understanding.

 

r/Steve

  • "Give me six hours to chop down a tree and I will spend the first four sharpening the axe."  -- Abraham Lincoln
  • "All right wise guy, where am I?"   -- Daffy Duck
  • "Well, we're safe for now. Thank goodness we're in a bowling alley."  -- Big Bob, Pleasantville