In the microscopic expression of current: I = NESV, s refers to the cross-sectional area. In the definition formula: I = q / T, it is said that it has nothing to do with the cross-sectional area. What is the reason?

In the microscopic expression of current: I = NESV, s refers to the cross-sectional area. In the definition formula: I = q / T, it is said that it has nothing to do with the cross-sectional area. What is the reason?

I = q / T is the definition of current, which does not involve area. Of course, it can be considered that I has nothing to do with area. This definition can be more accurately understood as: the amount of electricity passing through a section in unit time. No matter how small the section is, as long as the amount of electricity passing through the section in unit time is equal, the current is considered equal