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Blown Serial to USB converter — Parallax Forums

Blown Serial to USB converter

TomOfPEITomOfPEI Posts: 5
edited 2009-02-06 20:49 in BASIC Stamp
I am working with a BS2 on a prototyping board which is powered by a 6.5 volt DC supply. When I connect a PC to the serial to USB converter, the converter blows. This does not happen when a battery is used. Do I have a grounding issue??

Any help would be appreciated.

Comments

  • dandreaedandreae Posts: 1,375
    edited 2009-01-30 15:58
    Can you post a schematic of your board?· This may help us determine the issue.

    Dave

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    Dave Andreae

    Parallax Tech Support·
  • TomOfPEITomOfPEI Posts: 5
    edited 2009-02-05 20:10
    Dave, thank you for the email response. I sent you the pdf of my circuit. I'm not sure the best way to "post" a drawing etc... Anyway. I found the problem, the voltage source that I am using has a floating ground which created the problem. I am solving it with a different power supply. On another matter though, I am using some outputs to switch opto-couples relays (as per the drawing), and am wondering why the voltage drops (at the output) to about 1.4 volts? The relays are CLARE LAA110 and have a spec. voltage drop of about 1.2 vdc typical.
  • lincolnlincoln Posts: 23
    edited 2009-02-06 20:49
    Hello,
    I will field a guess that you 1.4v voltage drop has to do with the Ron of 25~35 and ohms law.....

    the only mention of a 1.2 voltage drop is on the led side of things

    link

    Post Edited (lincoln) : 2/6/2009 9:06:47 PM GMT
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