I did a deep dive in this topic as an EE undergrad and I'm here to report that trying to actually understand these things will end in disappoint, not withstandi

I did a deep dive in this topic as an EE undergrad and I'm here to report that trying to actually understand these things will end in disappoint, not withstanding all of the cargo cult mumbo jumbo that gets past off as education in this area. My personal experience was that after badgering the prof week after week for a full term his final answer was "I don't know. Go and ask Dr. Soandso in the physics department" It takes a lot of effort to track down the essential contradiction. In short the problem is "holes" and "electrons" stuff. In particular the "holes". In the beginning because of doping and band gaps and such the doping atom releases and electron into the conduction band which leaves behind a positively charged "hole". Ie the atom now has one more proton than electrons. So far so good. But a few weeks later we move on to the Hall Effect and now these "holes" are moving and this allows the hall effect to distinguish the N-type from the P-type (qv X h, and all that). But that can't be right because the positive charge is fixed with the doping atom and not moveable so the v should be forever zero. Well of course the actual technology does work but the theory it's based on is far too difficult for mortal EE's (and their profs) to understand so instead they (the physicists) cooked up a bogus theory with a fatal flaw (conservation of charge - where does this new moving proton come from?) and everyone is happy cuz they never thought it through. My recommendation is to save yourself a lot of time and worthless effort and work on the water flowing through a pipe analogy. This can take younquite a long way with DC circuits and extends with a few tweaks to ac circuits as well. And with respect to transistors. I read through all the comments here and as far as I can tell no one distinguishes between bipolar and FET transistors. These are very different beasts with very different operating characteristics but, cutting to the chase, both behave very much like a water tap type. With bipolar transistors the "gate" current allows a proportionally much large current to flow through the other two leads so it's and amplifier of current. Simple as that. Rotate the tap a bit and get a much bigger resonse in the water flowing. With FET transistors the "gate" is controlled by voltage rather than current (there is a little leakage current but it's tiny) but the result of a larger current though the other two leads is pretty much the same. Capacitors and inductors are readily added to your repertoire. When you hit phase locked loops though you're gonna have to crack some books. In theory, practice and theory are the same. In practice they're not.