I’m a bit confused about capacitors. I understand they store energy in a field by accumulating opposite charges on the different plates. So a 1 farad capacitor will store 1 coulomb of charge if subjected to 1 volt if I understand the math right.
1 coulomb is also 1 amp-second, so this capacitor can supply 1 amp of current for 1 second.
Now what I don’t understand is where voltage comes into this. Can this theoretical capacitor only run 1V loads? Why? Wouldn’t a .5 farad capacitor subjected to 2V also store 1 coulomb of charge? What would be the difference between the charge stored in these two capacitors?
Best Answer
Answering the second comment to the question.
Yes, that is exactly correct. They would both be storing 1C of charge. Think of a capacitor like a (perfect) balloon where the larger the capacitance, the larger the balloon volume and the more you expand the balloon, the higher the pressure inside the balloon.
Imagine one really huge balloon, and one really tiny balloon (this is only to illustrate the point.)
Imagine you wanted to fill both balloons with 5 lung fulls of air, and afterward, you pinch off the orifice. I think it is easy to imagine the really huge balloon not being very full at all after 5 lung-fulls, where the small balloon is almost full to bursting.
The pressure in both balloons corresponds to the voltage, and the amount of air in each balloon (5 lung-fulls) corresponds to the amount of charge stored in each capacitor.
Does this help illustrate the relationship between charge, capacitance, and voltage?