There exists only one current in a circuit: What I take that to mean is simply that there is a movement of electrons through the circuit wires. Does that mean that electrons move at different speeds at distinct parts of a circuit like, say, before and after a resistor? No, that would imply a different dQ/dt, therefore different currents. I'm confused as to how we can measure different voltages before and after a resistor in a circuit, but the current be the same along the circuit.. Any simple circuit like the picture attached.. There is a voltage drop across the resistor, but if there's different voltages, why not different currents? The question came up looking at this thread: https://www.physicsforums.com/showthread.php?t=316323" where each of the 6 LED's in series, for instance, each require 15 mA. If the same current occurs through all the LED's, then all you'd need to figure out is the equivalent resistance, yes?