How do resistors work in series? [duplicate]

Question

I know that current is same in a series circuit becuase the current only has one path to flow but I'm confused on how resistors work in series. From what I've read is that current is the same before and after a resistor (Eg. if 500ma flow into a resistor 500ma flow out of the resistor) so what is the resistor actually limiting?

Answer 1

The resistor is limiting the kinetic energy gained by the charge from the voltage source by simultaneously dissipating it as heat, so that the kinetic energy of the charge (and thus current) is constant.

The mechanical analogy is pushing an object at constant velocity on a surface with friction. The positive work done pushing the object (analogous to the work done by the voltage source) equals the negative work done by kinetic friction of the surface, (analogous rt the negative work done by the resistor) so that the change in kinetic energy of the object (change in current entering and exiting the resistor) is zero per the work energy theorem.

Hope this helps.

Answer 2

the resistor dissipates energy by reducing the voltage in the circuit. continuity requires that the current into a resistor = current out of the resistor.

Here is how to think of resistors in series.

For convenience, we will model a resistor as a long skinny length of a resistive material, like carbon. We will now string two of these lengths of carbon together, one after another, in the circuit.

Now imagine we eliminate the piece of wire connecting them so the first length of carbon butts up right against the second length of carbon in the circuit. Now we have one piece of carbon twice as long as before, which has twice the resistance as before. It will pass half as much current for a given source voltage as did the single length of carbon, which had half the resistance.