I have some questions that I am struggling to understand. Due to my situation I don't have much chance to experiment much and am stuck doing a lot of book learning. I understand how to solve for basic circuits.

Here are my questions:

1.) House circuits have 120v 15A, however if I divided 120v by a load of 2ohm I would get 60AMPS. Obviously this is not the case. Do wall sockets have a natural resistance of 8 ohm thus giving 15A? How is it that you can switch to a 20amp socket? How many amps are actually running through a circuit? I understand most houses have 100amp breakers and sometimes larger, is there a transformer in it to drop the amps?

2.) what is the voltage and amps of a typical residential powerline? How about the large lines? Is there a resource on the site with this information?

3. I am sort of stumped by the idea of total circuit current. For instance, if I have a basic circuit with a parallel section of 3, 2ohm resistors connected to 12 V source, they would be equivalent to 2ohms. Each would have its own branch current as well of 2amps adding to total I of 6a. Here is where I am confused, if I was to connected another path after the furthest most resistor , but before it meets at the shared node where all branch currents combine, would any load I hook up to that have only the individual branch current pushing through it?

I think what I am struggling with in any circuit design is whether to create essentially numerous parallel circuits that split right off at the source and that only recombine after their loads function has been accomplished or whether it is useful to hook different components up in series.. The entire idea of branch current is confusing. do we determine total circuit current just as a mathematical device to check our work or does it help us determine the actual voltage and current present at certain points? can the voltage and current be different in the same circuit?

Example, if I had a 12v source connected to a 2ohm load there would be 6amps. This would be 72 watts. However, if I added another 2ohm resistor in series I would now have 3amps and only 36 watts. However the voltage drop at each would be equally 6v. in the first example all 12v were applied to the first resistor, but how many volts and amps would read if you measure after that resistor? How many after the second resistor in example 2?

4. Wall worts confuse me.. How is it that they are dropping the voltage and current? A giant resistor? It cant be an inductor in there because where did all the extra voltage and current go?

5. in a transformer I understand that the ratio of primary to secondary winding effects the relationship because voltage and current.. however, what effect does the size of the magnetic wire used in the turnings play? besides that smaller wire allows for more turns? if I had two transformers with the same ratio but with different gauges what would be the practical differences?