PCB Design - Is it OK to use "jumpers" for single sided design

Discussion in 'General Electronics Chat' started by spinnaker, Feb 14, 2010.

  1. spinnaker

    Thread Starter AAC Fanatic!

    Oct 29, 2009
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    I am a newbie to PCB design. Since I am a newbie, I went with single sided to make things easier.

    I was able to design the PCB for my power supply fairly easily. I am guessing because I had components with a low pin count.

    Now I am designing the DMM portion. I am a number of components with a higher pin count.

    I am struggling to route everything without traces crossing one another. In some instances I have been able to pass a trace under a component.

    I was wondering if it was permissible to use "jumpers" (or what ever they are called) to bridge traces, using the top side of the board.

    I am guessing if they are used, they should be used sparingly?
     
  2. BMorse

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    Sep 26, 2009
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    You can use jumpers if you want, I do all the time when making double sided PCB's at home.... here is a PCB I recently just made with some jumpers on top, I used the leads that are cut off of resistors and the diodes that I used in the circuit for the jumpers...

    [​IMG]
     
  3. t06afre

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    May 11, 2009
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    Of course you can use jumpers. I often use jumpers to get rid of a routing problem in my hobby projects. And components like resistors make excellent jumpers.
     
  4. Duane P Wetick

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    Apr 23, 2009
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    I've used insulated or un-insulated jumpers on single sided pcb's to economize costs. You can even buy 0 ohm resistors if you don't want to use wire. For feed-thru terminal blocks, its best to use plated-thru holes and double side pads because screw torques sometimes want to lift solder pads.

    Cheers, DPW [ Everything has limitations...and I hate limitations.]
     
  5. SgtWookie

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    Jul 17, 2007
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    Sure, you can use jumpers.

    It's best if you can minimize their use, because otherwise you will have more holes to drill, more wires to solder/trim, and more points that could cause you problems.

    Try to place jumpers in just one rotation; either 0° (Y-axis) or 90° (X-axis). If you start using jumpers in both rotations, you'll likely find yourself "boxed in" in a hurry.
     
  6. dsp_redux

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    Apr 11, 2009
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    Like t06afre mentionned, try to use resistors or components from your circuit as jumpers. Make sure you don't short the traces with the component tough.
     
  7. retched

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    Dec 5, 2009
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    0 ohm resistors are used as jumpers often in surface mount board work. You can feel free to jump all you want. It can become a problem in higher frequency applications. All the jumpers can work as extra antennae leading to unwanted noise in your project.
     
  8. spinnaker

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    Wow!

    Thanks for all of the quick and great responses. I am glad to see even the pros use this practice and on double sided boards too.

    Yes I know I can use components as jumpers. I did this a lot on the power supply version of my project.

    I figured added jumpers were kind of the "goto statement" of the PCB world. :) Try not to use them, but if you do minimize them. From the sounds of it though, it is almost not as bad as using a goto. :)


    Is it also acceptable to make kind of a hybrid PCB / (sort of) perf board? Using wire wrap wire to make connections from pin to pin? Yes I know minimize them. But is some acceptable?

    If so, (for a newbie) is this preferable over narrower traces and trying to weave trace in between pins?

    I know I have seen wire wrap on professionally designed boards before but I am pretty sure that was after the fact, for either fixing a mistake or upgrading the design without having to toss out the whole board.
     
  9. k7elp60

    Senior Member

    Nov 4, 2008
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    I use the prefabricated colored jumpers that are used on proto boards for jumpers. The colors specify the length in 0.1"s of inches.
     
  10. spinnaker

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    So you are saying that you use point to point wiring on a PCB or you use the prefab colored jumpers just as jumpers?
     
  11. SgtWookie

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    Jul 17, 2007
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    Try to avoid making your board look like a hybrid spaghetti. ;)

    Don't forget that since you're using a uC, you have lots of options to swap I/O pins around. Frequently, that just involves changing a few lines of programming or port mapping. Just start off with routing those that can't be reassigned, like the Vcc/Vdd, Vss/GND, and your MCLR pin (if you're using it with an in-circuit programming/debugging connector; not a bad idea to do so with such prototypes).

    You may have several I/O pins to choose from for the ADC or comparator inputs.
    Then routing the other I/O lines comes last.
     
  12. spinnaker

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    Yep already made some changes of pins! :)

    And I think I can make a couple of more.

    I might get it down to where I only have one or two point to point wirings and 2-3 jumpers.

    I can really see where, you may need to go back to the orginal design and change that. Then maybe breadboard it, then go back to your PCB.

    Though I guess more experience, helps in the original design.

    ExpresspCB should really think of turning this into a video game. They would make a fortune. :)
     
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