# electronic component questions



## PC person (Feb 2, 2006)

I've been watching a series of lectures here, on basic electronics here:

nptelhrd - YouTube

Here's what I'm confused about

1. Capacitors- To charge one, you connect the positive end to one the plates and the negative end to the other. I can understand how the plate gets positively charged, the battery takes electrons away from the plate, but what about how it adds electrons to the other plate? With the positive terminal has holes in which the electrons from the wire and plate rush to fill, why would electrons go to fill the plate which is negatively charged? That plate and wire is electrically neutral, as far as I know, it's atoms already have the amount of electrons to equal the amount of protons, so how would electrons travel from the negative terminal to the plate

And, it is said here 

Lecture - 3 Electronics Devices - YouTube

at 46:42 that capacitors in series add up. But, I don't understand this diagram. You see those two plates? Those are the capacitors I'm guessing. With the one on the left, the left-most plate is either the positive or negative plate, and the next left- most plate is it's opposite. A capacitor is a path between the two plates, one negative, one positive. So, how would the electricity get from the negative to the positive plate if there's no connection between them? I don't see how you can have them in series

Variable capacitors- one way to make one is to have the plates be adjustable, so you could for example, move them away from each other. How does this work? By moving them away from each other, so they have a shorter path to follow to the other plate via the wire , so if you connect the two plates, it has a lower resistance- a shorter route to get there, and thus more current, or does effect how much electricity is stored (farads) somehow?

A variable capacitor is also a component in an oscillator. How would it work specifically if say, I wanted to tune into 98.5FM on my radio, how varying the capacitor would allow me to do it. Then, perhaps furthermore, how the pattern of information (whatever form it takes) is decoded and produced as audible sound, yes I've been trying to understand radio for a while as well.


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## PC person (Feb 2, 2006)

Didn't mean to post the whole video, just the link to it


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