Finding I(0)- and I(0)+ in First Order Circuit

[darwinharianto]

the question is to find I(0)- and I(0)+
the I is at the

what I have attempted
finding Req on the right side
I eliminate the capacitor and Req = 12*6/(12+6) = 4
so Vc (0)- = Req/(Req+12) *18 = 9/2

T = Req*c= 4*1/12 = 1/3
so V(t) = 18/4 e^(-3T)

so I (0)- = V(t)/12 = 3/8 e^(-3t)

but I don't know how to find the I(0)+


sorry for bad English and bad picture
thx for replying in advance

 

[ehild]

Be a bit more specific: What are I(0)+ and I(0)-?

ehild

 

[darwinharianto]

Be a bit more specific: What are I(0)+ and I(0)-?

ehild

its the current that before and after time = 0
a moment right after for +
a moment right before for -

 

[baby_1]

Hello darwinharianto
See the attachment.

 

[darwinharianto]

Hello darwinharianto
See the attachment.

oic
thanks a lot

so no need for me to the e^x
because the assignment before got e^x for the V

 

[baby_1]

Hello darwinharianto
as you know before t(-) we assume that our circuit is in steady state so we don't have exponential form.however after t(0) capacitor tries to be discharge with RC period time so exponential form will appear.
if you want exponential form of i after t(0) follow the attachment.

 

[darwinharianto]

Hello darwinharianto
as you know before t(-) we assume that our circuit is in steady state so we don't have exponential form.however after t(0) capacitor tries to be discharge with RC period time so exponential form will appear.
if you want exponential form of i after t(0) follow the attachment.

thanks a lot :D
now I do understand it