Here is the problem: What is the instantaneous value of charge current exactly after two time constants?
For:
TC=RC=0.01uF * 15kΩ = 150us 2TC= 300us t=elapsed time = 2TC = 300us ic = instantaneous current @ Cap
Imax = V/R = 40V/1500Ω = 26.67mA
ic = Imax (1 - e^-t/(RC)) = 26.67mA (1 - e^-300us/150us) = 26.67mA(1 - 0.135335) = 23.061mA
And 2TC = ~86% .: 0,86 * 26.27mA = 22.592mA
So those 2 approaches seem to agree but the answer key gives 360.69uA. And that is my quandary...
The -t/(RC) = -2 and e^-2 = 0.135335
I don't see the error?
For:
TC=RC=0.01uF * 15kΩ = 150us 2TC= 300us t=elapsed time = 2TC = 300us ic = instantaneous current @ Cap
Imax = V/R = 40V/1500Ω = 26.67mA
ic = Imax (1 - e^-t/(RC)) = 26.67mA (1 - e^-300us/150us) = 26.67mA(1 - 0.135335) = 23.061mA
And 2TC = ~86% .: 0,86 * 26.27mA = 22.592mA
So those 2 approaches seem to agree but the answer key gives 360.69uA. And that is my quandary...
The -t/(RC) = -2 and e^-2 = 0.135335
I don't see the error?
Last edited: