Sorry if this question is stupid, but I can't find any answers for this online.
Physics websites show that capacitors charge and discharge exponentially. The discharging graphs of charge against time show a 'normal' exponential decay graph. However, the charging graphs don't look the same as other exponential growth graphs. Instead of the quite flat line then steep curve, it is a steep curve from 0 which levels off. Why is this?
When I reference 'normal' graphs I mean the ones at Wikipedia (http://en.wikipedia.org/wiki/Exponential_decay and http://en.wikipedia.org/wiki/Exponential_growth).
I understand the basics of physically how a capacitor charges and discharges, I just don't understand why the charging graph doesn't look like other exponential increase graphs. Is this just my lack of understanding of maths?
Best Answer
The curves show a charging that is proportional to
$1-\mathrm{exp}(-t/\tau)$.
Essentially, you should flip the exponential decay graph upside down.