Razavi Basic Circuits Lec 19: Shortcut Method for First-Order Systems

[reneg]

something creating confusion is this : the standard equation of the shortcut is written as: alpha(dy over dt) + y = x(t)
next we see a calculation of y(t) using y(inf) and meaning the x(t) is y(t)....
in the first example we calculate I1(t) with this putting I(inf) and I (0) in the arguments... and again x(t) seems to be y(t) so the standard formula looks to be alpha(dy/dt) + y = y(t)


all good so far, until the second example : here we see V1 = R1C1(dVout/dt) + Vout(1 + R1/R2) a little shocking, since V1 is a constant and not a function of

some algebra however solved this since by deviding all the terms by (1 + R1/R2) the V1 in the equation transformed into Vout and alpha(dy/dt) + y = y(t) is now respected....

hope my confusion can help some people going looking into these quit nice lessons

[reneg]

u(t) keeps dropping out of nowhere....