**Fig. 11.6.** Determination of the voltage between two points at or within the surface of a volume conductor.

(A) The potentials Φ

_{i} and Φ

_{j} at P

_{i} and P

_{j} due to the dipole

may be established with scalar products with the lead vectors

_{i} and

_{j} , respectively.

(B) For determining the voltage

*V*_{i j} between P

_{i} and P

_{j}, the lead vector

_{i j} =

_{i} -

_{j} is first determined.

(C) The voltage

*V*_{i j} is the scalar product of the lead vector

_{i j} and the dipole

.