# Constant Boundary Condition

**URL:** <https://community.freefem.org/t/constant-boundary-condition/147>\
**Category:** General Discussion\
**Created:** [October 3, 2019, 4:16pm UTC](https://community.freefem.org/t/constant-boundary-condition/147 "2019-10-03T16:16:43Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![robin997](https://avatars.discourse-cdn.com/v4/letter/r/dfb087/32.png) [@robin997](https://community.freefem.org/u/robin997)\
**Post date:** [October 3, 2019, 4:16pm UTC](https://community.freefem.org/t/constant-boundary-condition/147/1 "2019-10-03T16:16:43Z")

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Is there a way to specify a constant boundary condition (in 3d)? I am doing analysis (capacitance, voltage, etc) of a composite electrical component. So we know that inside a conductor, we have no electric field, thus constant voltage. To model this constant voltage, I can set a very high conductance parameter, but then the solver seems to be unstable - So instead, is there a way to set constant voltage condition wherever a conductor is present?

The equation is, simply,  
Laplacian of (epsilon \* V) = 0