AC couple pin to GND?

Discussion in 'General Electronics Chat' started by Vindhyachal Takniki, Mar 23, 2015.

  1. Vindhyachal Takniki

    Thread Starter Member

    Nov 3, 2014
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  2. Reloadron

    Active Member

    Jan 15, 2015
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    No, here is what our friends at NI say:

    If we have an AC signal riding on a DC component level using a cap in the line will block the DC component. Here is the NI pdf on the subject.

    Ron
     
  3. Vindhyachal Takniki

    Thread Starter Member

    Nov 3, 2014
    348
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    @Reloadron yes the link I got what ac & dc coupling mean.
    But in my circuit I have to ac couple a pin to GND. Does that mean that I have to connect a capacitor between pin & gnd like a decoupling capacitor.
     
  4. #12

    Expert

    Nov 30, 2010
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    That's what it sounds like, but "in my circuit" makes this look like you sent us to a reference that has nothing to do with your circuit. How are we supposed to guess what YOUR circuit needs?
     
  5. Reloadron

    Active Member

    Jan 15, 2015
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    Anytime since a capacitor passes AC and blocks DC you connect AC to to a capacitor that is going to a ground you have effectively shorted your AC signal to ground and thus this makes no sense. DC power pins use a decoupling capacitor to ground but coupling an AC signal to ground makes no sense. Would really need to see a schematic or drawing of what you are talking about.

    Ron
     
  6. Ramussons

    Active Member

    May 3, 2013
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    The term "ac couple" in this context is ambiguous. The term "couple" is used when we want to pass on signals for further use - amplifying, filtering, etc. "bypass" or "decouple" is the term used when "ground" comes in.

    You need to show a schematic or a explanation for us to infer what actually you mean in this particular case.

    If we do away with the terminology, "Yes" is the answer to your question.
     
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