In all diagrams i have ever seen of circuits it's implied that electrons travel through load/bulb and bulb makes light/heat.

Now there is a problem here...because of this implied logic i assumed more electrons that follow more power and therefore after power is used in light their speed reduces. But that doesn't make sense what's happening with clogged up electrons.

-coming electron and leaving electron both are the same. I assumed, that unused electron somehow was bigger and puffed and when it gets used its small/slow/ or less charged..But it's none of the above. It's actually the same...So i learned energy is carried via waves that travels through electrons.

Now i don't know what is current or electricity. If used and unused electron both are the same what provided the energy.

please explain how number of electrons, speed of electrons, wave(?) of Energy, and all other stuff fits into how electricity works.

  • 1
    $\begingroup$ Related: physics.stackexchange.com/q/54995 $\endgroup$
    – mcodesmart
    Commented Oct 11, 2013 at 19:18
  • $\begingroup$ Note that current is not the same as electron flow. Electrons cannot flow across a good capacitor, but electric currents can. AC currents indeed carry energy through "waves"; in DC currents you need to be able to describe a box which has real electrons flowing into and out of it. $\endgroup$
    – CR Drost
    Commented Feb 25, 2015 at 21:02

1 Answer 1


It's easy to think of it in terms of something maybe more familiar - flow of fluid in pipes.

Suppose you have a closed loop of pipes. In one part of the closed loop is a pump. In another is something like a hydraulic motor, that converts moving fluid into mechanical work.

The pump is like a battery. The hydraulic motor is like an electric motor. (A light bulb is not much different from a motor - it just converts electrical work into heat, rather than mechanical work.)

So the wire loop is just like a pipe loop, and the electrons in the wires are just like the fluid molecules in the pipes, and they flow the same way. (Pipes can leak if they have holes, but wires don't (at low voltage), because the electrons in the wire are "attached to" the metal and can't easily take off on their own.) (I'm simplifying here.)

The amount of them that flow past a point in one second is called "current". The pressure is called "voltage". The work done in the hydraulic or electric motor in one second is just the current times the pressure-drop or voltage-drop across it.

  • $\begingroup$ so... what is current how energy is supplied. If everything else after and before remains the same. $\endgroup$ Commented Oct 13, 2013 at 21:33
  • $\begingroup$ @Muhammad: Think of the hydraulic analogy (incompressible fluid, like water or oil). The hydraulic motor has pistons, against which the fluid pushes, doing work. It can only push against the pistons if it has higher pressure on one side, and lower on the other. So it comes into the motor at high pressure and comes out at low pressure. Same thing with electricity, the voltage is higher going into the motor (or light bulb) than it is coming out. That pressure difference, times the flow rate, is the power. $\endgroup$ Commented Oct 14, 2013 at 0:01
  • $\begingroup$ again this analogy had me believing that movement of electrons carry energy when it's the movement through, a wave, that carry energy electrons actually very slow. $\endgroup$ Commented Oct 14, 2013 at 13:35
  • $\begingroup$ @Muhammad: Right. The electrons in the metal actually move slowly, just like water in a pipe does not move very fast, but since the fluid is fairly incompressible, the wave of pressure in it moves very fast. In water, the pressure wave moves at the speed of sound. If you turn on the valve, water starts flowing "immediately" at the other end of a long pipe. In a wire, it is closer to the speed of light (1m/3ns). But again, the energy in the electrons is proportional to voltage, and in the water it is proportional to pressure. $\endgroup$ Commented Oct 14, 2013 at 17:10
  • $\begingroup$ so electrons push each other...or as i read that a field is generated in a cascading style so it's a field that act as a wave. at this point i want to know how energy is carried in this wave like in wire what causes heat. And why do you need both - and + to cause movement in electrons. If i attach - part to a bulb it should light up as there are electrons pushing/whatever. $\endgroup$ Commented Oct 14, 2013 at 17:15

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