I'm for the most part an electrical newbie, although I have made a guitar amp. I am the type of person who doesn't like to do things when I don't understand what I'm doing. I was wondering how many electrical hobbyists/engineers actually understand electronics, and how many are just working with numbers, symbols, and formulas. Throughout the building of my amp I asked my physics teacher(he's the best I have, I'm in highschool) about how certain components work, and what amperage and voltage really mean. I have a ton of questions, if anyone could direct me to a site that could explain these things I would be grateful. I understand the flow of electricity and stuff, but, for example, if you change the resistance in a circuit, does that also change the current or the voltage? And do resistors really just turn energy into heat, like my teacher said, or do the just restrict it's flow?