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Determining Capacitance between Multiple Conductors

Posted Sep 13, 2014, 6:18 p.m. EDT Version 4.3a 4 Replies

Chris Reilly
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Hi,

I have a system with 3 conductors as in the attached image. The first (left) conductor is set to a terminal boundary with V = 1. The second (right) conductor is set to a terminal boundary with V = 0. The last one (the floating conductor) is set to floating potential with Q0 = 0.

However, I'm not able to measure the capacitance between terminal 1 or 2 and the floating conductor (the only options are C11, C12, C21, C22). What boundary condition should I be using on the floating conductor to allow me to measure the capacitance?

Thanks,
Chris

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4 Replies Last Post Sep 18, 2014, 3:17 a.m. EDT
Edgar J. Kaiser Certified Consultant
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Posted: 1 decade ago Sep 14, 2014, 3:13 a.m. EDT
Hi Chris,

well for the purpose of measuring the capacitance make it a terminal as well, since capacitance only depends on the geometry (and the medium between the electrodes). For other purposes make it float again. The capacitance will remain the same.

Cheers
Edgar

--
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Hi Chris, well for the purpose of measuring the capacitance make it a terminal as well, since capacitance only depends on the geometry (and the medium between the electrodes). For other purposes make it float again. The capacitance will remain the same. Cheers Edgar -- Edgar J. Kaiser emPhys Physical Technology http://www.emphys.com
Chris Reilly
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Posted: 1 decade ago Sep 14, 2014, 1:19 p.m. EDT
Thanks Edgar, that approached worked.
Thanks Edgar, that approached worked.
Chris Reilly
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Posted: 1 decade ago Sep 16, 2014, 7:17 p.m. EDT
Hey Edgar, another quick question. I'm trying to show that by increasing the permittivity and conductivity of the top conductor, the capacitance seen at the right (sense) conductor increases. However, when I set the three conductors to measure the capacitance, I get no change in capacitance when the relative permittivity or conductivity are altered. I also get the same effect when setting the left terminal to 1V, the right terminal to 0V and floating the top electrode.

Any ideas on how to demonstrate this? See the attached paper if you have any questions, I'm essentially trying to replicate their results in figure 4 and 5.

Thanks,
Chris
Hey Edgar, another quick question. I'm trying to show that by increasing the permittivity and conductivity of the top conductor, the capacitance seen at the right (sense) conductor increases. However, when I set the three conductors to measure the capacitance, I get no change in capacitance when the relative permittivity or conductivity are altered. I also get the same effect when setting the left terminal to 1V, the right terminal to 0V and floating the top electrode. Any ideas on how to demonstrate this? See the attached paper if you have any questions, I'm essentially trying to replicate their results in figure 4 and 5. Thanks, Chris
Edgar J. Kaiser Certified Consultant
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Posted: 1 decade ago Sep 18, 2014, 3:17 a.m. EDT
Hi Chris,

the "quick" question actually requires a lot of reading. I quickly browsed through the document and one thing I noticed is that they use AC excitation. Is your model taking this into account?

Cheers
Edgar

--
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Hi Chris, the "quick" question actually requires a lot of reading. I quickly browsed through the document and one thing I noticed is that they use AC excitation. Is your model taking this into account? Cheers Edgar -- Edgar J. Kaiser emPhys Physical Technology http://www.emphys.com

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