Hello peeps, im currently studying capacitors and simple electronic circuit design, but im getting the feeling im not quite fully understanding things because i keep forgetting key concepts and how they fit together in an abstract sense.(adsbygoogle = window.adsbygoogle || []).push({});

(please forgive the long post, its an attempt to get everything out and shake out any misunderstandings and uncertainties, I'll Add my succinct questions to the end)

Some Background:

I am trying to learn what capacitors are used for, and how to go about selecting the right capacitor for a given problem or circuit design.

I understand that capacitors are used for storing charge and as filters, in the form of band-pass/stop high/low-pass filters. I beleive that this filtering is due to the frequecy response of the capacitor as an oscillating system, in which it takes time to fully charge a capacitor plate and that this is a property of the capacitor material and the current and voltage. I think of this analogus to a pendulum oscillating system attached to some damping device.

I have learned how a capacitor stores charge by seperating charges with a dielectric (non-conducting) material, and that there exists an electric field between any two seperated charges. The energy held by a capacitor is a measure of the potential work that the capacitor can do, when the seperated charges are allowed to flow back to equillibrium.

I beleive that i am correct in saying it is and applied voltage accross the capacitor that maintains the charge seperation accross the dielectric material?

In terms of circuit design i have seen how a capacitor may be used in conjunction with a resitor to create a filter, but i cant say i fully understand how the two components work to acheive this.

Im terribly confused. I dont quite understand what an electric field is, other than a seemingly abstract concept which sais that "If you roll this ball of charge away from that ball of charge, then the work you put in you will get out eventually when they roll back together again" (conservation of charge & energy laws).

So my main Questions:

- [1]What properties make a good dielectric material? (on a molecular and/or subatomic level of detail).

- [2]In a resistor, electrical charge is converted to thermal energy, by what mechanism is this acheived? (again, this is mostly a question of molecular mechanics i guess).

- [3]If i was designing a circuit that required a certain frequency filter, what would help me decide on the Capacitor type and rating and the resitor type and rating?.

(you'll notice my complete lack of mathematical skill here, sorry in advance)

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# Understanding Capacitors - Form & Function

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