Simple Question on PCB Trace Routing

Discussion in 'General Electronics Chat' started by madscientistdan, Aug 20, 2012.

  1. madscientistdan

    Thread Starter Member

    Mar 6, 2012
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    I've noticed that sometimes when the 45 degree part of the trace is really short and hard to see and it looks like a line coming off the pad that is off-center.

    Is this a bad thing or not really? I've attached a screen shot of an example. The purple line is the trajectory of the trace I have now but as you see it looks off center on R18 because the 45 degree bend is so small. I could follow the blue line trajectory so it doesn't look off-center but then the signal goes through an extra bend.

    Is what I have fine or will an expert electrical engineer consider my trace to look bad aesthetically? In particular the trace connected to R18 looks like a straight line off-center. It looks a little funny visually to me since it looks off-center since the bend is really short but maybe that doesn't really matter?

    [​IMG]
     
    Last edited: Aug 20, 2012
  2. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    I am not an expert ee, but I have laid out a lot of PCBs and I think you made the right choice. The trace you are concerned about is no different from the one on the top right of R17.
     
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  3. madscientistdan

    Thread Starter Member

    Mar 6, 2012
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    Thanks. I'm just not sure if it looks OK aesthetically? Would an expert electrical engineer say it looks bad aesthetically? It almost just looks like an off-center straight line connected to R18 since the 45 degree bend is so short.
     
  4. cork_ie

    Member

    Oct 8, 2011
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    The general rule is: If the circuit is low frequency, then inductance and capacitance of the tracks are unlikely to have any impact. Crosstalk is also rare but possible, especially in audio.
    In that case the main criteria are the track resistance and layout to suit the components.

    At higher frequencies especially when working with RF at VHF and higher frequencies, capacitance & inductance are crucial in the design and it is common to see tracks taking circuitous routes.Some of these layouts look distictly odd but are designed that way for a reason. It is also possible to see baluns for impedence matching (like Celtic designs) etched onto the board.
     
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  5. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    If you want to make it look better, pull that corner to the left so that it lines up with the corner on the trace just under it.
     
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  6. madscientistdan

    Thread Starter Member

    Mar 6, 2012
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    Thanks,
    I was trying to preserve 45 degree or horizontal/vertical traces.

    If i only pull that corner to the left, then I won't have a 45 degree angle bend. I could pull that corner left and follow the blue trajectory in the image but then I have added an extra bend if I want to keep all 45 degree angles.

    I prefer not to move the location of the resistor. Would most people just leave the trace as I have it now? I can't see anything wrong from a functional point of view.
     
  7. cork_ie

    Member

    Oct 8, 2011
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    Yes it is fine.
     
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  8. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    If you pull that corner to the left and keep the upward trace at a 45, it will intersect the square pad higher than it does now, but it should still mirror the trace underneath it.

    In answer to your question, I would try what I just suggested, decide whether I liked it better that what I have now, make a choice, and move on with life. The fact is that unless you move a pad or give up on all 45's, the only choices you have left are just what I described. I could tell you it's not worth obsessing over, but I have been know to do the same thing. :)
     
    Last edited: Aug 20, 2012
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  9. steveb

    Senior Member

    Jul 3, 2008
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    I would leave it and not even notice it as a problem if looking at someone else's board. Unless you are doing a detailed electromagnetic study of the board (i.e. RF or microwave work) there is no logic in being too picky about little things like this. Yes, there is always some concern about aesthetics, but this just does not rise to the level of looking bad. - at least by my standards.
     
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  10. MrChips

    Moderator

    Oct 2, 2009
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    Nope. Nothing wrong with that. I do it all the time.
     
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  11. madscientistdan

    Thread Starter Member

    Mar 6, 2012
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    Thanks so much for all of your help. I will leave the trace as is.
     
  12. JMac3108

    Active Member

    Aug 16, 2010
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    I do it this way all the time too. No big deal.
     
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