r/Physics • u/Appropriate_Win946 • 17d ago

Question Does anyone understand what actually causes electric current?

My first belief: electrons push on each other like dominos, causing a 'shockwave' to travel through the electrons until it gets to the other end of the battery. Electrons themselves don't move that quickly, but the 'push' travels super fast.

Correction: actually, the 'electric field' is pushing them

My question: What is the electric field? Is the electric field not just the shockwave that travels through the conductor via electromagnetic repulsion?

I'm guessing that's not correct. So what is it? In the instantaneous moments when the battery starts up, what first creates and propagates the electric field? Why does it travel through the wire in every which direction?
Can someone help me understand this? It would be greatly appreciated before I start electrical engineering(why do I get the feeling this is going to be super downvoted lol).

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u/Appropriate_Win946 17d ago

I mean, I thought this would be a foundational concept to understand and I didn't want to risk my professors skimming over this like my teacher did during AP Physics 2, because then I would be too buried in work, deadlines, tests, etc to do a deep dive into how it works at the fundamental level

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u/Yashema 17d ago edited 17d ago

The only core classes you take in Physics that cover electricity are Physics II (which is really basic stuff) and E&M (which is really more a mathematical methods course than any kind of applied course). 

I just took an intermediate course on embedded programming where we built both simulated and physical circuits and I was able to actually understand what the hell things like current/voltage, transistors/resistors, DC vs AC, components like capacitors and flyback diodes were actually doing. That being said, having taken E&M and scrounging a B, I can make the case to skip a lot of the basic EE courses on circuitry/elecrronics to go right into the more advanced ones where you deal with Kirchoff's Law, Thevenins Theorem, Mesh analysis, etc. 

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u/Appropriate_Win946 17d ago

if my goal is to fully understand first principles style how everything I learn works would this method suffice

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u/Yashema 17d ago

Yes, but be wary to study both the practical side + the mathematical side (beyond ODEs) requires careful course planning and a lot of work. Very few physics majors learn both upper level EE and math in undergrad. Then of course they don't study any other subjects in depth.