# How can current be constant and still result in resistors having a voltage drop?

My issue arises when thinking about the situation like this. Current is the amount of charge flowing through an area, and resistance is basically they difficulty in doing so. My issue results when thinking about how current can be constant while resistors still causing a voltage drop.

If I think about the current being constant then the amount of charge flowing into and out of the resistor must be the same and therefore the Individual charges are spaced the same and there total electrical potential remains the same because no work is done by the electromagnetic force (Yes in reality some is for there would be no current if there weren't a potential difference across the resistor but my point is the resistor itself doesn't cause the voltage drop but rather the E field due to the battery)

What am I not understanding?

Edit. I get that the increased resistance (collision with molecules) results in a loss of energy threw heat. But electrical potential is the potential energy due to the electric force, and that only depends on the distance of charges from each other which cant change if current remains constant

• You might find this interesting: physics.stackexchange.com/q/143300 Also: physics.stackexchange.com/q/186614 Commented Nov 24, 2021 at 19:39
• see that just makes me more confused for is there must be a difference in charge density then how can current be consent when a higher density moving through an area at the same time would mean a change in current? Commented Nov 24, 2021 at 19:46
• The current density is the charge density times the velocity (to zeroth order you can ignore the word density and say that current is charge times velocity if that helps). If the charge density is higher, then for the current to stay fixed, the velocity must be lower. So in a wire you have an open road with a few charges whizzing by, in resistor you have a traffic jam where a lot of charges are taking a long time to pass through. But the number of charges passing per unit time is the same in both cases. Commented Nov 24, 2021 at 19:50
• Ok so to use an analogy you have ball rolling down a hill and the get to a funnel, even thou the amount of of balls(charge)increases there ability to travel decreases as they move through the funnel until they come out the other end and spread from each other as there speed increases once again, the more funnels you add the more the build up effects other parts of the system with the least density of balls at the end (Lower Potential) then at the top (Higher potential) Commented Nov 24, 2021 at 20:02
• That sounds right to me. The current of "fast but few" balls can be the same as "slow but many balls" so long as the product "velocity times number of balls" is the same. Commented Nov 24, 2021 at 20:05