A current I Amps flows through a capacitor at time t seconds is given by:

I=#(1-e^((-t)/τ))

where the time constant τ is 0.8 seconds. Determine:


(i) The current

after (12 + ∆) seconds.

(ii) The time taken for the current to reach (8 + ∆) amps

 

Sorry I am new to this site, this is my first post.

Do you know how I can put this in the home work section?

Hi,

Bertus moved it for you

Now, what does your number symbol mean in your post "#" is that the voltage or current or something else ?
Maybe you could rewrite that in a more clear form.

 

Hello,

Do you mean 3 instead of the # ?
Can you show your attemp to solve the problem?

Bertus

PS I revomed some posts that are not needed anymore.

 

Welcome to AAC!
We can help you, but don't do the homework for you.
Are there any constraints on Δ?
Show us your best effort.

 

Thanks for moving it for me.

I am totally perplexed by this problem.

As far as I know # is an unknown number that needs to be worked out. It is written as that in my assignment question.

Bertus, you are a genius yeah it's a mistake by my college it is supposed to be 3 definitely.

I will get back to you if I need any more help I should be able to work this out now knowing that the college made a typo.

Best regards.

 

In the problem of uncertainty, there is a lack of numerical data (eg #)

 

My guess is that Δ might either be an independent variable (though it is two different parameters since one is a time and the other is a current) or it might be a student-dependent parameter so that each student is working a different problem.

 

Do you get extra points for realizing that there is no physical circuit where the current through a capacitor begins at zero and rises to some constant value (beyond 5τ)?

 

Do you get extra points for realizing that there is no physical circuit where the current through a capacitor begins at zero and rises to some constant value (beyond 5τ)?

Hi,

Yes, this would normally be I*e^(-t/tau) unless they want the student to just take it verbatim.