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how exactly resistor works

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iMo:
Ohm's and Kirchhoff's and alike laws or rules are just simplifications people in the electronics use in order to make their life much easier.
If you want to understand how the stuff works you must study this:
https://en.wikipedia.org/wiki/Maxwell%27s_equations

Btw, a typical standard Q during exams from "Theory of Electromagnetic fields" subject the EE students usually get is to derive the Ohm's law from the Maxwell's equations.

palpurul:
It's kind of irrelevant, but here is a quote for you from a very respectable physics book called "introduction to electrodynamics" by David J. Griffiths

“I don't suppose there is any formula in physics more widely known than Ohm's law, and yet it's not really a true law.”

ArthurDent:
Every law or rule has an exception, if you're picky, but for real world practical use I'll go with what a sage once told me: "Ohm's law is definitive."

djacobow:

--- Quote from: imo on September 29, 2018, 06:02:28 pm ---Ohm's and Kirchhoff's and alike laws or rules are just simplifications people in the electronics use in order to make their life much easier.
If you want to understand how the stuff works you must study this:
https://en.wikipedia.org/wiki/Maxwell%27s_equations

Btw, a typical standard Q during exams from "Theory of Electromagnetic fields" subject the EE students usually get is to derive the Ohm's law from the Maxwell's equations.

--- End quote ---

If you examine such derivations, you'll see that they rely on the assumption that the number of free charge carriers and the relaxation time (the average lifetime of a charge carrier) are constants and do not change endogenously with the electric field or current density. But again, that is true only for certain materials.

This is a beginners forum, so I understand that it is not a good idea to answer more than what was asked. But in giving a limited answer, I think it is important not to say something that is fundamentally wrong, least it become a fundamentally wrong building block for their entire understanding of electricity for their whole lives. Ohm's Law is presented incorrectly almost all the time when it could be presented correctly just as easily: ohm's equation explains the simple, linear relationship between current and voltage in many - but not all - common materials.

djacobow:

--- Quote from: ArthurDent on September 29, 2018, 06:48:22 pm ---Every law or rule has an exception, if you're picky, but for real world practical use I'll go with what a sage once told me: "Ohm's law is definitive."

--- End quote ---

The exceptions merely form the basis for the entire modern world as we know it.

Life would be a LOT more boring if we only had ohmic materials.

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