# How many volts will be across the capacitor at the second time constant?

Discussion in 'Electronics Homework Help' started by charmcaster.engg, Jan 28, 2015.

1. ### charmcaster.engg

79
1
Mar 20, 2014
An 8 V power source is charging a capacitor. How many volts will be across the capacitor at the second time constant?

4,098
875
Jun 25, 2014

3. ### LvW

604
146
Apr 12, 2014
What is the first time constant? How do you define it for this task?

4. ### davennModerator

13,674
1,892
Sep 5, 2009
As usual this OP has given very little info and made no attempt at an answer

Dave

5. ### charmcaster.engg

79
1
Mar 20, 2014
I google n get, after the first interval, the capacitor voltage equals 63.2% of the battery voltage. In the second time interval, the capacitor picks up 63.2%, not of the full of battery voltage, but 63.2% of the of the difference between the starting charge(5.056) and the battery voltage(8V). I am on right track to solve the question?

6. ### Gryd3

4,098
875
Jun 25, 2014
You sure are
Good job.

Of course, now that you know the magic numbers, you can play with the math to make it easier

79
1
Mar 20, 2014
Thanks!