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capacitance between multiple plates

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good morning;

i have a three plate 2D problem and i would like to calculate the capacitance between the relevant plates. over what surface do i need to integrate to get capacitance?

when i calculate capacitance do leave the 3rd plate floating if i compute the capacitance between plate 1 and 2?

i am using comsol 4.2

any help would be greatly appreciated
regards
gerhard

7 Replies Last Post Aug 28, 2015, 7:51 a.m. EDT

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Posted: 10 years ago May 28, 2015, 4:44 a.m. EDT
Hello,

the easiest way to calculate capacitance is the to use terminals. Here, the capacitance is measured to GND. If you apply a terminal sweep you can also calculate the relevant capacities C12, C13, ...

I have attached a simple model.

kind regards,
Levin Dieterle
Hello, the easiest way to calculate capacitance is the to use terminals. Here, the capacitance is measured to GND. If you apply a terminal sweep you can also calculate the relevant capacities C12, C13, ... I have attached a simple model. kind regards, Levin Dieterle


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Posted: 10 years ago May 28, 2015, 5:10 a.m. EDT
Good morning Levin;

thank you very much for the response, by the terminal method i am assuming global evaluation -> capacitance?
do you by any chance have a tutorial on capacitance matrix's?

thank you for the help
regards
gerhard
Good morning Levin; thank you very much for the response, by the terminal method i am assuming global evaluation -> capacitance? do you by any chance have a tutorial on capacitance matrix's? thank you for the help regards gerhard

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Posted: 10 years ago May 28, 2015, 5:34 a.m. EDT
Hi,

I don't have a tutorial in COMSOL. However, here is a good explanation:
www.fastfieldsolvers.com/Papers/The_Maxwell_Capacitance_Matrix_WP110301_R01.pdf

kind regards,
Levin
Hi, I don't have a tutorial in COMSOL. However, here is a good explanation: http://www.fastfieldsolvers.com/Papers/The_Maxwell_Capacitance_Matrix_WP110301_R01.pdf kind regards, Levin

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Posted: 10 years ago May 28, 2015, 5:53 a.m. EDT
Hi ;

thank you very much!

regards
gerhard
Hi ; thank you very much! regards gerhard

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Posted: 9 years ago Jun 3, 2015, 7:46 a.m. EDT
Hi Levin,
can you also provide me the model ?
I use COMSOL 4.3b.
Hi Levin, can you also provide me the model ? I use COMSOL 4.3b.

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Posted: 9 years ago Jun 18, 2015, 3:01 a.m. EDT
Hello Dejan,

the model is attached to one of the previous posts.

Kind regards,
Levin
Hello Dejan, the model is attached to one of the previous posts. Kind regards, Levin

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Posted: 9 years ago Aug 28, 2015, 7:51 a.m. EDT
Hi I saw your discussion and I want to do exactly the same.

I have 3 electrodes (see figure attached). I want to know the capacity of each electrode with the grounded on the top of my box. I tried to implement everything as in your "capitance matrix.mph" file.

I have two grounds. I don't know if the matrix calculates the capacitance from the electrodes to the ground on the top of my box. Or the capacitance to my middle electrode, which is at ground.

How can I see which capacitance it gives me?


(and a small other question, if I apply a terminal on a good conductor, it is sufficient to just assign the terminal to one surface of the conductor, or do I have to select all surfaces)
Hi I saw your discussion and I want to do exactly the same. I have 3 electrodes (see figure attached). I want to know the capacity of each electrode with the grounded on the top of my box. I tried to implement everything as in your "capitance matrix.mph" file. I have two grounds. I don't know if the matrix calculates the capacitance from the electrodes to the ground on the top of my box. Or the capacitance to my middle electrode, which is at ground. How can I see which capacitance it gives me? (and a small other question, if I apply a terminal on a good conductor, it is sufficient to just assign the terminal to one surface of the conductor, or do I have to select all surfaces)

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