# Art of Electronics Question 1.14

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1. Apr 14, 2015

### DrPapper

1. The problem statement, all variables and given/known data

There is a circuit diagram which I can't post atm and don't think it's relevant to my question.

Also: R1
=R2=10k and C=.1μF

And: Find V(t)

2. Relevant equations

We're given the equation V(t)=1/RC ∫t-∞ Vi(t)e-(t-τ)/RC

My problem is I don't recall what tau is here "τ" and I'm not sure what I should be using for the Vi(τ).
I've been trying to find it in my notes and physics textbooks but I can't seem to find it. LOL I must be stuck on stupid because I know I've seen these and am familiar with them. If anyone has this book and has solved this problem please help me out. :D

3. The attempt at a solution

Found V(t) by Thevenin Analysis to be .5Vi also used Thevanin to find Req=20K to replace the 1/R in the integral. Not sure what else to do.

2. Apr 14, 2015

### BvU

$\tau$ is an integration variable, with the dimension of time. "How long ago" is what it stands for: V(t) depends on what happened before.

No more free advice until you follow the guidelines: your complete and concise problem statement, all the given and unknown variables; the equations you intend to use and not the results of your attempt at solution, but your attempt.