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Squiggly traces on a PCB? — Parallax Forums

Squiggly traces on a PCB?

RonPRonP Posts: 384
edited 2011-11-22 09:54 in Robotics
Hello All,

I just scrapped a computer someone tossed out. I noticed the Mother Board has quite a few traces that are squiggly(for lack of a better word). Does anyone know the reason for this type of trace? Just curious.

Ron





IMG_0279.jpg
IMG_0279.jpg
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Comments

  • Duane DegnDuane Degn Posts: 10,588
    edited 2011-11-17 14:39
    Ron,

    I've also seen those. I assumed they were to keep the timing correct for those lines. If some traces of a data bus are long while others are short I suppose it could cause problems with fast computers. Maybe they use the squiggles to make the bus traces all the same length. That's my guess anyway.

    Hopefully someone here knows the real answer.
  • RonPRonP Posts: 384
    edited 2011-11-17 14:41
    Duane,

    That's kinda what I thought also. Never saw them before, something new to me.

    Ron
  • LeonLeon Posts: 7,620
    edited 2011-11-17 14:55
    Yes, some tracks need to be the same length in some situations, usually in high-speed designs. The Pulsonix PCB software I use creates them automatically, and adjusts their lengths, if they are needed.
  • RonPRonP Posts: 384
    edited 2011-11-17 14:58
    Leon,

    Thanks for the clarification. Now I must ask is there any other reason(s) one might use such a trace?

    Ron
  • LeonLeon Posts: 7,620
    edited 2011-11-17 15:02
    It could be used to delay a signal by a small amount.
  • RonPRonP Posts: 384
    edited 2011-11-17 15:08
    Leon,

    Thanks again. Learn something everyday.:smile:

    Ron
  • TubularTubular Posts: 4,646
    edited 2011-11-17 21:08
    If you look very closely at the Spinneret, down near the status LEDs, you'll see the same squiggly traces. Its easier to see on the pcb layout
    Spinneret2.jpg
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  • RonPRonP Posts: 384
    edited 2011-11-18 00:22
    Tubular,

    I see them. I don't have a Spinneret yet or I would have noticed them on that board. Every time I get a new board I get out the magnifying glass an give it a once over. A later google search produce the process "serpentine routing" so now the squiggly lines have an official name Serpentine Trace I guess. Cool.

    Ron
  • davejamesdavejames Posts: 4,047
    edited 2011-11-18 11:13
    If there's PCB real estate available, it's economical to build the delay lines with board traces.

    Go here:
    http://forums.parallax.com/entry.php?178-Of-Things-Buttons-amp-Latches...

    and at the bottom is a picture of a delay line device that could be used if there isn't enough room on the board.
  • RonPRonP Posts: 384
    edited 2011-11-18 12:05
    davejames,

    Very interesting thanks. I should check the blog section of this site more often. Now I wonder how much more I have missed.
    I am going to go take a look at the Spinneret schematic and PCB and see what they have the serpentine trace hooked up to.

    Ron
  • davejamesdavejames Posts: 4,047
    edited 2011-11-22 09:54
    RonP wrote: »
    Very interesting thanks.

    Very welcome - glad it offered some insight.
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