Voltage and current relations for capacitor?

Discussion in 'General Electronics Chat' started by vead, Aug 15, 2016.

Nov 24, 2011
621
8
Hello
I need help, I don't understand how to find out voltage of capacitor when voltage increase or decrease? I see the below formula. I plotted current time graph please help me

2. wayneh Expert

Sep 9, 2010
12,374
3,226
Is this homework?

Your setup looks OK. What's the problem? What is the analytical expression for i(t)?

3. crutschow Expert

Mar 14, 2008
13,475
3,362
You are asking to find the capacitor voltage when the voltage increases or decreases, which makes no sense.

The capacitor voltage change is the integral of the current (which is the total charge) into (or out of) the capacitor over time.
What don't you understand about that?

Nov 24, 2011
621
8
No I plotted graph just for my understanding. Any you asking the value of t1 and t2

Nov 24, 2011
621
8
Please look at formula, I want to find out voltage V

6. crutschow Expert

Mar 14, 2008
13,475
3,362
Do you not know how to do the integration in the formula?
That's how you calculate the capacitor voltage.
If not then you need to start studying calculus.

Nov 24, 2011
621
8
Look at handy calculation

8. ErnieM AAC Fanatic!

Apr 24, 2011
7,435
1,625
The handy calculation omitted the 1/C term. Otherwise it looks good to me.

9. DGElder Member

Apr 3, 2016
347
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So what happened to C and Vo?

10. WBahn Moderator

Mar 31, 2012
18,085
4,917
How did your i(t) suddenly go to just being t?

On what basis, given the plot of i(t) you showed, are you claiming that i(t) = (1 A/s)·t between t = 2 s and t = 4 s?

What happened to the capacitance?

If you would bother to track your units (which I have warned you about repeatedly) you would have seen that the units on your answer don't work out to volts. The fact that you refuse to track your units only proves that you don't really care about getting the answer correct.