1. The problem statement, all variables and given/known data In series RLC circuit how much time it takes for capacitor to charge to 0.63% of source voltage..? time constant is the time taken by a capacitor to charge to 0.63% of source voltage and in rc circuit time constant is RC. but what about for capacitor in series RLC circuit..? 2. Relevant equations 3. The attempt at a solution I searched allover the web and Wikipedia but i didn't find anything. i saw a formula saying that time constant is 2L/R and some where i saw time constant as 1/R*(L/C)1/2.but i don't know it is for inductor(L) or capacitor(C) and how to relate it to capacitor voltage. .