How do I build simple circuits?

[NascentOxygen]

Devices 'take' only the power they need. All the power they take, they use. Much/most of the power used ends up as heat, one way or another.

If you connect a number of resistors (or light bulbs) in series, it might appear that each is taking only a fraction of the power and passing the rest on to the next. That is a confused (and confusing) view of what's going on. Power is volts x amps, and each is using all of the power it gets, though in the case of series connections, each is getting a fraction of the applied total voltage.

 

[eng90]

I don't really know if the resistor is using 9 amps of power. It is resisting the flow of electrons, so that only 1 amp is flowing. The other 9 amps are not actually being sent out of the battery. So there is no way its wasting 9 amps. So I don't really know how much power it is using.

I think you have a decent understanding of how each of the components in the circuit work. But I think you would benefit from learning about circuit analysis. If you look online there are free lectures that you can watch and gain the same knowledge. The link below is to MIT but there are plenty more available on the web.

http://ocw.mit.edu/courses/electric...tronics-spring-2007/video-lectures/lecture-2/

 

[DruidArmy]

Thanks for the lecture link. I've watched the whole MIT series before on physics with that funny professor who has now retired. Very good lectures. I liked it when he levitated a blow up doll using a simple winding and 110v house current, using induced eddy currents. On his final lecture he attached a fire extinquisher to his tricycle and rocketed off the stage. Ha Ha.

Yes, I'm going to build some circuits (12v) and test voltages around it. I'm not sure my water hose analogy is good. Cause if i had a series of holes in it, I'm not sure if the flow (current) would be the same across all sections.

hose= --------0-------00-----000-----> the holes represent different resistances

Still trying to figure out the mechanics of what's really happening inside the wire and resistors.

 

[f95toli]

Still trying to figure out the mechanics of what's really happening inside the wire and resistors.

Don't worry about that at this stage. There is -fortunately- no need to understand the underlying physics to understand circuit theory. It is better to think about the various components as "black boxes" with some functionality.
This is even more true later on when you start working with integrated circuits such as op-amps, where you -quite literally- have no idea what is inside and you have to rely on the manufacturers datasheet to understand the properties.

Also, feel free to use the water analogy if it helps, just remember that it is only works in the very simple cases and shouldn't really be used for anything but circuits with only voltage/current sources and resistors.