Class l Help Assignment 3 Begin Date: 2/10 2018 4:0:00 PM- Due Date: 314/2018 11

Question

Class l Help Assignment 3 Begin Date: 2/10 2018 4:0:00 PM- Due Date: 314/2018 11:59:00 PM End Date: 3/6 2018 11:59:00 PM (4%) Problem 23: Suppose you wanted to charge an initially uncharged 125 pF capacitor through a 55 MS2 resistor to 90.0% of its final voltage Randomized Variables C=125 pF How much time (in s) would be required to do this? Grade Summary 490 96% Potential sino cotan asinO tan() | ( acos) cos) Submissions Attempts remaining: 1 % per attempt) detailed view atan acotan sinho cosh tanh cotnho O Degrees O Radians END 2% RACKSPACE DEL CLEAR 2% Submit Feedback I give up Hints: 2-for a 0%, deductiun. Hints remaining: Feedback: 2 for a 0% deduction -How does the voltage of a charging capacitor depend on time? The dependence is exponential, but make sure you use an expression ollowing that has zcro potential at o. The answer provided was not corect. We have recognized the - Your answer appears to be off by a factor of 10h, where a is an integer value. Ensure you have represented the number in the correct

Explanation / Answer

voltage after t sec is v = E*(1-e^(-t/T))

given that E = final voltage

v = 0.9*E

then

0.9*E = E*(1-e^(-t/T))

0.9 =(1-e^(-t/T))

0.9 = (1-e^(-t/T))

T = time constant = R*C = 125*10^-12*55*10^6 =0.006875 sec

then

0.9 = 1-e^(-t/0.006875)

t = 0.0158 sec

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