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Using a boundary's Voltage value in formulas
Posted Dec 13, 2010, 5:42 a.m. EST Low-Frequency Electromagnetics, Materials 3 Replies
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Hello everyone,
I've been working on a simple N-type Semiconductor model in COMSOL. The model involves injection of electrons on one boundary, and their diffusion to the other boundary.
One of the formulas requires the voltage value across one of the boundaries.
I've been trying to get it done using "Integration Coupling Variables" but to no avail.
I've attached a picture of the device with the appropriate text labels.
Any help would be greatly appreciated.
Thank you very much,
Halil
I've been working on a simple N-type Semiconductor model in COMSOL. The model involves injection of electrons on one boundary, and their diffusion to the other boundary.
One of the formulas requires the voltage value across one of the boundaries.
I've been trying to get it done using "Integration Coupling Variables" but to no avail.
I've attached a picture of the device with the appropriate text labels.
Any help would be greatly appreciated.
Thank you very much,
Halil
Attachments:
3 Replies Last Post Dec 22, 2010, 3:08 p.m. EST
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Posted:
1 decade ago
Hi
ihn 3.5 or 4 this should work if you define a voltage V1 and V2 at each boundary and take the difference in a global variable.
But you must decide a little how to:
1) you assume your two boundaries (where you estimate the voltage) are perfect conductors (or thereabout), this means you could take the voltage on any point on the boundary (apart that the edges or points at edge limits) might heritate also some additive properties from the other adjacent edges/boundaries. Or you calculate the average voltage along a boundary/edge by integration (aveop() in v4, or coupling_integration(V) / coupling_integration(1) in v3.5a) and use this to define youre V1 respectively V2. And then you add a global variable DV=V2-V1
2) your boundary is not really a perfect conductor and the voltage along the boundary/edge varies with the exact positon, hence the gap voltage is also dependig on the position. The use of an average operator is then not good. You must use som mapping operator to map the V1 varying voltage onto the second bounary and then define the difference there
--
Good luck
Ivar
ihn 3.5 or 4 this should work if you define a voltage V1 and V2 at each boundary and take the difference in a global variable.
But you must decide a little how to:
1) you assume your two boundaries (where you estimate the voltage) are perfect conductors (or thereabout), this means you could take the voltage on any point on the boundary (apart that the edges or points at edge limits) might heritate also some additive properties from the other adjacent edges/boundaries. Or you calculate the average voltage along a boundary/edge by integration (aveop() in v4, or coupling_integration(V) / coupling_integration(1) in v3.5a) and use this to define youre V1 respectively V2. And then you add a global variable DV=V2-V1
2) your boundary is not really a perfect conductor and the voltage along the boundary/edge varies with the exact positon, hence the gap voltage is also dependig on the position. The use of an average operator is then not good. You must use som mapping operator to map the V1 varying voltage onto the second bounary and then define the difference there
--
Good luck
Ivar
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Posted:
1 decade ago
Hi Ivar,
My name is Omer and I'm Halil's partner.
First of all, thank you for your quick answer.
We used your solution for perfect conductors by using Integration Coupling Variables. but now we need to make a more realistic model and for that we need option 2 - not a prefect conductor. so now we need to calculate the potential difference for each point. Can you please elaborate about the mapping operator?
Thank you very much,
Halil and Omer
My name is Omer and I'm Halil's partner.
First of all, thank you for your quick answer.
We used your solution for perfect conductors by using Integration Coupling Variables. but now we need to make a more realistic model and for that we need option 2 - not a prefect conductor. so now we need to calculate the potential difference for each point. Can you please elaborate about the mapping operator?
Thank you very much,
Halil and Omer
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Posted:
1 decade ago
Hi
you need then to define first how you define the two corresponding points, one on each surface, to then get a voltage by difference, it could be by a normal prjection or by another mean.
Now your non-perfect surface might still be sufficient to provide a rather uniform voltage value so the projection definition might not be that wrong
--
Good luck
Ivar
you need then to define first how you define the two corresponding points, one on each surface, to then get a voltage by difference, it could be by a normal prjection or by another mean.
Now your non-perfect surface might still be sufficient to provide a rather uniform voltage value so the projection definition might not be that wrong
--
Good luck
Ivar