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Mutaja

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**Charging/discharging of capacitor.**

## Homework Statement

Attached to this post, I have two circuits. The left, circuit 1. The right, circuit 2.

For circuit 1 I'm supposed to compute T (tau). Find the expression for U

_{c1}(t) and I

_{R1}(t). This is regarding discharging of a capacitor.

For circuit 2, I'm supposed to compute T, U

_{c1}(t) and U

_{c1}(∞)

## Homework Equations

## The Attempt at a Solution

For circuit 1:

Doing this for a series circuit is straight forward. For parallel circuits, from whatever I can see in my notes and my book, I'm supposed to convert this circuit into a thevenin equivalent. When I do that, using C1 as load, pressing in the switch and other wise use my knowledge about thevenin equivalent circuits, I get R to be 0. When V1 is short circuited, the "current" will flow through the resistance free path, avoiding R1.

How to I solve this?

And my mathematical expressions for U

_{c1}and I

_{R1}, would they differ any from what I have from a series circuit (identical to circuit 1 here, only R1 and C1 are in series)

There I have:

T = RC = 4700Ω * 680*10

^{-6}F = 3.196S

U

_{C1}= V

_{1}*(1-e

^{-t/Tau}) = 8v*(1-e

^{-t/3.196s})

I

_{R1}= V

_{1}*e

^{-t/Tau}= 8v*e

^{-t/3.196s}

#### Attachments

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