RL circuit with current source at different time intervals

Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
9 replies · 2K views
dwn
Messages
165
Reaction score
2

Homework Statement



Image


Homework Equations



Current divider

The Attempt at a Solution



The only thing I see is that I solve for R1 and R2 for t < 0. Other than that I'm confused and not even sure I'm right about solving t<0.
 

Attachments

  • Screen Shot 2014-05-08 at 9.27.32 PM.jpg
    Screen Shot 2014-05-08 at 9.27.32 PM.jpg
    8.8 KB · Views: 607
Physics news on Phys.org
Up until t=0, what is the equation for current through R2?

How does the circuit change at t=0?
 
Current Divider : 2 ( R1 + R2)/R1

The source is gone, stuck in the closed loop (essentially), and the inductor becomes the current source (the energy within the inductor decays exponentially).
 
dwn said:
Current Divider : 2 ( R1 + R2)/R1
That fraction is > 1.0 ?

The source is gone, stuck in the closed loop (essentially), and the inductor becomes the current source (the energy within the inductor decays exponentially).
So what is the general form of the equation describing this decay?
 
Oh no I'm sorry, it should be 2* ((Rtotal/R1))
Rtotal = (R1*R2)/(R1 + R2)

Ie-Rt/L (R equivalent)
 
dwn said:
Oh no I'm sorry, it should be 2* ((Rtotal/R1))
Rtotal = (R1*R2)/(R1 + R2)
Which resistor carries that current?
 
R2, if I'm not mistaken.
 
dwn said:
R2, if I'm not mistaken.
Guessing is not advisable. Don't you have some way to work it out?
 
Of course, the reason I put that was bc the forum requires min 4 characters...

We choose the "unwanted" resistor to divide from the total because it has something to do with impedance (never covered this topic in class). I know the larger the resistance the less current flowing through it.
 
Last edited:
NascentOxygen said:
Guessing is not advisable. Don't you have some way to work it out?

The bread crumbs are not helping.