# Capacitor in AC Circuit: Why there is such relation of current and voltage?

http://imageschip.com/image-2CC0_4D720BE9.jpg

In AC circuit when the voltage is zero the current is maximum...
When it reaches to 90 then the current is zero...
And same as for the other cycles till 360...

Why the current is maximum when the voltage is zero and when the voltage is maximum the current is zero...?

Please explain...

## Answers and Replies

uart
Science Advisor
The current is proportional to the rate of change (derivative) of voltage.

can u explain it a bit more?

uart
Science Advisor
$$i = c \frac{dv}{dt}$$

Do you know what "rate of change" is?

thnx... it helped....

uart can u apply some values on the above formula that u have mentioned?

did i written something wrong?

Dale
Mentor
2020 Award
did i written something wrong?
Yes. From the https://www.physicsforums.com/showthread.php?t=414380" "In the interest of conveying ideas as clearly as possible, posts are required to show reasonable attention to written English communication standards. This includes the use of proper grammatical structure, punctuation, capitalization, and spelling. SMS messaging shorthand, such as using "u" for "you", is not acceptable."
thnx... it helped....

uart can u apply some values on the above formula that u have mentioned?

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