Hello all!

I am really stuck up here. I have made this circuit and want to measure the voltage across the capacitor. The voltage should gradually increase as the capacitor charges, and then become constant. But, I only get a constant voltage of 6V across the capacitor.

Infact, I have to measure the time constant. I am doing a transient analysis, and when I plot the voltage, it just shows a straight line, and no rising trend.

Please help!

The circuit image can be seen at:

http://img641.imageshack.us/img641/8897/rccircuit.jpg

 

Thats going to rise pretty darn quick.

Did you set your analysis start state with the cap at 0v?

 

Thanks for the quick reply.

Can you please tell me how to do that ?

 

What software are you using?

 

I am using PSPICE v9.1 Student Edition

 

You're looking for the checkbox "skip the initial bias point calculation" under simulation settings.

 

Thanks for replying.

I managed to solve the problem by setting the initial condition of the capacitor to 0V.

 

Hello, I recommend you to use Spice2g6. I know nothing about version 9.1
I think the reason you´re not getting any indication of increasing voltage is because it happens very fast, that capacitor is very small, you should use at least a 1000uF one.

A yeah, I mean if you´re trying to measure the real circuit. In Spice theres no problem with time.

 

Thanks for replying.

My problem has been solved by setting the initial condition of the capacitor to 0 V.

Cheers!