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why the metal plate of a capacitor is defined to be made of air instead of being a kind of metal in "capacitance model 12689"

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Hi all,

I was looking at the "computing capacitance" model 12689, and I figued out that the metal plate material is defined to be made of air.
Why we do not define the metal plate material as a kind of metal, and leave it to be built by air?!
The link to access the model is:

www.comsol.com/showroom/documentation/model/12689/

4 Replies Last Post 20 set 2012, 10:03 GMT-4

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Posted: 1 decade ago 20 set 2012, 09:29 GMT-4
Sarah,

in this electrostatic model the material doesn't really matter. The two plates are set to terminals at 0 and 1V and this and the geomertty are the only things that affect the field in the static case. Things get different in a non-stationary case and with currents. Then the conductivity must be assigned to the domains.

Cheers
Edgar
Sarah, in this electrostatic model the material doesn't really matter. The two plates are set to terminals at 0 and 1V and this and the geomertty are the only things that affect the field in the static case. Things get different in a non-stationary case and with currents. Then the conductivity must be assigned to the domains. Cheers Edgar

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Posted: 1 decade ago 20 set 2012, 09:54 GMT-4
Thanks Edgar,

if I want to consider the plate material as a parameter which affects the field, which model should I use?
Thanks Edgar, if I want to consider the plate material as a parameter which affects the field, which model should I use?

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Posted: 1 decade ago 20 set 2012, 10:01 GMT-4
That depends on your model. If it is about low frequency AC you would probably choose emf, if high frequencies are involved you must switch to RF.
That depends on your model. If it is about low frequency AC you would probably choose emf, if high frequencies are involved you must switch to RF.

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Posted: 1 decade ago 20 set 2012, 10:03 GMT-4
thanks alot for your help

thanks alot for your help

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