I'm not well versed in electrostatics and had this question no one could help me with (even after searching on the internet) : I have a surface (with its resistance increasing by 1kohm per centimeter²) and I have an electric battery (EB) with voltage 9V and intensity 2A connected to it at A (+) and B (-).
Elsewhere, on the surface, I have two electrodes C and D at a known distance of A. I want to know how far I will measure something (i.e. more than 0.001V) in C (the potential in C, or the difference of potentials between C and D) i.e. I'd like to know which formula to use linking "distance A-C", "conductivity of the surface", "voltage and intensity of the input current" and "current in C" (wanted).
You will find an attached picture to clarify my question : 
