# What is the current before arriving a resistor and after leaving it in the wire?

Suppose we have a very simple circuit, with just a resistor between a wire connected to a power source. What's the actual value of current travelling the wire before and after the resistor? Is it different? Or is it the same across the wire, between the power source?

My guess is that it should be the same, since the resistor limits the current flow, thus create a "congestion" for the current that goes through it. This congestion also slows down the current before entering the resistor and lessen the overall electrons flow through the wire because the resistor is limiting the total amount of electrons that can pass the resistor. So even if the wire can carry more electrons, but the resistor is limiting it, the wire only supplies the amount of electrons allowed by the resistor and the amount of electrons actually on the wire are the same as the maximum go through the resistor. Is this correct?

• Don't analyze circuits by thinking of electrons moving in circles around a circuit. Electrons themselves physically traverse a DC circuit very slowly, and don't traverse an AC circuit at all (they just wiggle back and forth). Electrons that are moving move on the order of meters per hour (or slower) - what actually does the work in a circuit is the electromagnetic field which moves at nearly the speed of light from the source to the load. The electrons provide a path for the propagation of the energy, they aren't the energy itself. Mar 9, 2014 at 1:56
• Thanks. So, is electromagnetic field actually a current if it's not a movement of electrons from the surplus of charge point to deficiency point? Mar 9, 2014 at 7:31
• amasci.com/elect/elefaq1.html#aelist Mar 9, 2014 at 13:24