Couple of questions

Thread Starter


Joined Sep 3, 2007
I have two question that I am having problems with. My first question is how do I find RMS voltage? In our notes in class our teacher did not go over that. MY second question is how do I find the time constant if I am given something like at t=37.5ms the resistor voltage is 1.115v. If it help I attached the assignment. I would appriciate any tips to get me started in solving these problems. Thanks



Joined Mar 21, 2007
For your first question, you can find the approximate R.M.S. value by multiplying peak amplitude by 0.707. (or divide by 1.414).
For your second question, you need to use the capacitor charge formula;

Vc = Vs . 1- e^-t/rc

t is 37.5ms, Vs is 5V, Vc is (5 - 1.115)

Make rc the subject of the equation, and solve for your answer.

Hope this helps,