How and why is voltage shared across all loads in a circuit?

Question

So I’m a beginner in electronics. I’m trying to teach myself because I never had a teacher to explain anything. One of my things is that it’s hard for me to understand something without fully understanding the fundamental basics, which has kept me from progressing in my self-study.

I can’t understand why electrical current shares its power across its loads in a circuit (series, obvs).

For example, a 12 volt battery is connected to a lamp. That lamp gets 12 volts of electricity running through its filaments (or LEDs or whatever). If there were 2 identical lamps in series, then that 12 volts would be split up between each lamp, which would result in them each getting only 6 volts.

But why? The electrons don’t know what the whole circuit looks like, they don’t know or care about how many loads there are. When the actual electron flow hits upon the first load in the circuit, why shouldn’t they act the same as if there is one load? Why would they behave as if there were more loads? At that time, when the electrons are meeting that first load, what makes them go, “only going to be half as bright, buddy”?

My dad tried to help by showing the equation of amps and volts and current, but that doesn’t answer my question at all. It only says it does do that, but it doesn’t tell me WHY.

In: Technology

Answer 1

Electrically an individual electron doesn’t need to flow through the entire circuit to transfer power. Instead something like say a battery will release some electrons, that pile into the wire pushing electrons ahead out of the way which then push other electrons out of the way until you get to the other end of the battery where completely different electrons are collected to replace the ones that were released.

The electrons don’t “know” what the whole circuit looks like yes, but they are still in contact and pushing against each other. The division of voltage drop is a consequence of this pressure evenly distributing itself throughout the circuit based on the loads resistance.

Mechanically think of having two identical springs stacked on top of each other. If you press them with some force the deformation of each identical spring is the same.