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**Capacitor Resistors problem, URGENT PLZ, exam preparation**

## Homework Statement

In the following transient circuit, assume at t<0, the circuit is at steady state.

Assume vc(t) is the voltage across the capacitor and v0 (t) is the output voltage as shown:

Find (a) vc(0+) (b) vc(∞) (c) vc(t) and (d) v0(t) for t>0

http://sphotos-b.xx.fbcdn.net/hphotos-ash4/c0.0.299.299/p403x403/381831_509320622420791_1588549456_n.jpg [Broken]

## Homework Equations

## The Attempt at a Solution

I am pretty first stuck right at the beginning

A)

For this part, the capacitor will act as "open", so I remove the capacitor.

But then I have no idea how to find the voltage.

B) After the switch is opened for ∞, we can again open the capacitor.

the 2K on the left will be out of the circuit as well?

so the voltage of the capacitor will be the same as the 4K on the right side?

the current will not go through the 2k in the middle?

if so, the voltage will be 6V?

C)we need V(0) for this and time constant. τ = c/Rth

to find R

_{th}we remove all source and take out the capacitor.

and again, I am not sure if the 2K resistors will be in series?

if they are then just take the equilvalent resistor

[(2+2)|| 4]+4 = 6k ?

and then just plug into the Vc(t) = (V(0) - V(∞)) e(-t/T) + V(∞)

D) Is Vo(t) = Vc(t) for t>0

since Vo(t) = V of 4K?

Thanks for your time

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