I find that there are two ways in which the relationship between electric field intensity and potential are expressed as mentioned hereunder: (A) E = - dV / dx (V = potential and x is the direction along which V varies) (B) E = - Delta V / Delta x My understanding of the application of (A) and (B) is as follows: (A) is the general case where the variation of V with x could be linear or non-linear, i.e. E could be constant or variable along the x direction. E represents the limiting value of an incremental value of V divided by an incremental value of x (at a given value of x) as the increment in x is made infinitesimally small. Thus E is the gradient of the V versus x graph at any given value of x. (B) is a specific case of (A) when V varies linearly with x, when E is constant along the x direction. In this case the value of E would be the same irrespective of the values chosen for Delta V or Delta x. I would appreciate if the above understanding could be commented upon / ratified. Thanks.