Time constant in RC circuit

Can you explain the function of resistor in LCR and RC circuit? Why time constant is taken only at o.36q in decay and 0.64 in growth of charge?

Asked Kiran

Answer:

We are studying the circuit containing a resistor and a capacitor. Further in almost all circuits there will be a resistance.

For the second part, you can easily see that decaying to 36% is same as decaying by 64%. Therefore the change that has taken place is same in both growth and decay.