graph of time constant rc network

[Guest bhuvaneshnick]

in the below image u see that time constant is 0.37 of initial value and 63% of final value.if that so see the second graph in that image the point should be on 0.37 (from initial value) but actually the time constant point is on 0.63.
this is messing with my i dont know what i misunderstood.

[Hero999]

Here's a hint:
37% = 100% - 63%

So if you have a 1uF capacitor and a 1M resistor in series, the time constant will be 1s.

If you start at zero and connect the circuit to 100V it will take 1 second for the voltage on the capacitor to reach 63V, that's 63% of the steady state value.

On the other hand, if you start with the capacitor fully charge to 100V and connect the resistor in parallel, the voltage will decay to 37V in 1 second.

[Guest bhuvaneshnick]

If you start at zero and connect the circuit to 100V it will take 1 second for the voltage on the capacitor to reach 63V, that's 63% of the steady state value.

okay i agree with you there is other statement that tou is 0.37 of initial value.in that way at time constant of 1s it should be at 37 right