The voltage source V2 is a unit step source which gives 100V after t = 0.

I want to know the equation of the instantaneous voltage across the capacitor. voltage becomes 500V(approx) after 60-70 seconds.

Ive tried to derive it but I dont think its correct.

Heres the equation:

vc = 100/((1/1 - e^t/RC) - 0.8)

vc is the voltage across capacitor and it controls the current through the independent source. Heres the schematic.

http://img12.imageshack.us/img12/8358/uploada.jpg

Any help will be much appreciated.

thanks.