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Capacitance between two adjacent long thin plates

  1. Dec 4, 2011 #1

    I am working on a project for the design of a capacitive sensor. In order to do that, I am required to compute capacitance using a simulation software like COMSOL. As I want to compare my simulation results with the theoretical results, I would like to know the formula to be used for the capacitance.

    It is not C= epsilon0*epsilonR*A/d as the plates are long and thin like this:

    ------------------- --------------------
    | | | |
    -------------------- ---------------------

    I hope this diagram makes sense. ( Consider the plates to be of large length ( in the order of 0.1mm) and very small width ( in the order of 0.005mm). I want to calculated capacitance between these two plates.

    Can you help me with the formula?

    Thanks for your help.
    Last edited: Dec 4, 2011
  2. jcsd
  3. Dec 4, 2011 #2


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    Your drawing isn't clear. Are the "plates" supposed to be coplanar and end to end (like a ribbon that, halfway down its length, has been cut across to make two shorter ribbons)? If so, there is no analytic formula for capacitance.
  4. Dec 4, 2011 #3
    Thanks for your reply.

    The plates are like as shown in attachment.

    Now, can you help me with the capacitance formula?

    Attached Files:

  5. Dec 4, 2011 #4


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    I don't know of any analytic formulas for this case.
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