Solid State Physics has a bunch of different types of models to try to explain the behavior of electrons in semiconductors and conductors. Most of them are onl

Solid State Physics has a bunch of different types of models to try to explain the behavior of electrons in semiconductors and conductors. Most of them are only valid under specific situations and they sometimes give erroneous results unless you apply them carefully. That being said, your absolutely right that the industry uses approximations. They usually use some kind of simulation physics package similar to the ones used by EE engineers when designing circuits.