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How to find Current and electric field ??

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Hello sir,

I am student. and learning this Comsol 4.2 software..so i need a help..

My problem statement is like,

one meter length semiconductor wire (Ge) and radius is 0.3mm. if i am applying 25V DC across the wire..
is it possible that comsol solve that how much current is flowing and electric field is there in the wire..

if it is possible than please some one who know guide me .. How to make this problem in Comsol..

Please reply as soon as possible..

Thank you so much for reading my problem..

2 Replies Last Post 7 août 2012, 00:18 UTC−4

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Posted: 1 decade ago 31 juil. 2012, 09:39 UTC−4
Hi,

1. there is a great documentation in comsol's software. You can find the answer of my questions right there (in the menu, Help->documentation)

2. In order to see the current flowing, you need to use Electric Currents interface in ACDC module. You can give DC voltage as choosing an electric potential (or a terminal). You should also choose a boundary for ground. After the simulation, you can see the electric field in study groups as choosing a slice (or surface etc.) and choosing Electric Field (norm or x or y or z direction) in the expressions part. Same for current density as well.

In order to see how much current flowing, you need to integrate the current density on the surface. For it, go to the defitions, from model couplings find out integration, choose your surface (where you wish the current amount), then open variables sub-window, type the current density (norm,x,y,z anyone you want) inside the integration as:

for example:
integration(ec.normJ)

You can find out more information regarding the procedure in doc.

--
physics undergrad
loves photon.
Hi, 1. there is a great documentation in comsol's software. You can find the answer of my questions right there (in the menu, Help->documentation) 2. In order to see the current flowing, you need to use Electric Currents interface in ACDC module. You can give DC voltage as choosing an electric potential (or a terminal). You should also choose a boundary for ground. After the simulation, you can see the electric field in study groups as choosing a slice (or surface etc.) and choosing Electric Field (norm or x or y or z direction) in the expressions part. Same for current density as well. In order to see how much current flowing, you need to integrate the current density on the surface. For it, go to the defitions, from model couplings find out integration, choose your surface (where you wish the current amount), then open variables sub-window, type the current density (norm,x,y,z anyone you want) inside the integration as: for example: integration(ec.normJ) You can find out more information regarding the procedure in doc. -- physics undergrad loves photon.

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Posted: 1 decade ago 7 août 2012, 00:18 UTC−4
thank you so much for your suggestion.

According to your instruction i have found the current density and electric field ..

but i could not find the exact surface integration of model..

can you explain the steps that how to do that.. Please.. here i am attaching you my 2D model..

if any correction is required please tell me..

thanking you
thank you so much for your suggestion. According to your instruction i have found the current density and electric field .. but i could not find the exact surface integration of model.. can you explain the steps that how to do that.. Please.. here i am attaching you my 2D model.. if any correction is required please tell me.. thanking you

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