I've read all the posts about this, but I still can't get this one thing: Why does current decrease if a resistor is put into the circuit? 1) there's a circuit without an 'official' resistor, only a wire that has small resistance. 2) there's a circuit with an 'official' resistor, and a wire that has small resistance. Both have a source. Now, in case 1), electrons simply bump into some atoms while accelerated by Electric field, then pick up speed, again. In case 2), E-field is still the same, there aren't more atoms for electrons to bump into before or after the resistor, only in it, and I'm not talking about electrons immediately leaving/entering the resistor, but the ones that are, say, 2 meters from a resistor (since they're pretty slow). The analogy the book gives is a pipe and incompressible flow; I can't accept this, as electrons are pretty small, don't practically repel each other in order to flow, and don't bump into each other (as to make any significant advances/pushes). The only explanation I've heard is that "the mean free path" is smaller, but I don't again see how that affects electrons that aren't near the resistor. I can only imagine them being slowed down exactly at the resistor's entrance, and then the rate will be lower, as they leave the resistor. That however implies making a full circle, because otherwise the electrons way after the resistor ought to be faster and denser (just like in case 1)). [I know about drift velocity, Voltage I believe is simply some newly made measure that's basically work, and is implemented by E-field, and I know that electrons do work while passing through a resistor, thus reduce their Potential Energy and thus Voltage.] Just one more example so you can tell me where's a flaw in my assumptions: Let's say we have a circuit like 1) with 10 electrons. They pass through some point A at the rate 10e/2s = 5 electrons per sec. Now let's make a circuit like 2) but put 5 electrons on both sides of the resistor. Now the group that's after the resistor must travel at same rate of 5e per sec, nothing is obstructing their flow (except the wire's resistance that I made obvious).