PDE

Hi

I have a 1D domain. The boundary conditions for electrostatic potential are given as 5 volts on the left boundary and the electric potential gradient on the right boundary is zero.

How should I represent a gradient value on a boundary? Which boundary condition should I use?

I tried to use the PDE general form, but I don't know how to couple the variable to my right boundary.

Your replies would be most helpful.

Thanks