Finding i(t) Across R3 & R2 After Switch Closure at t=0

  • Thread starter Thread starter vthokie11
  • Start date Start date
  • Tags Tags
    closure Switch
AI Thread Summary
To find the current i(t) across resistors R3 and R2 after the switch closure at t=0, it's essential to recognize that the inductor behaves like a short circuit before the switch opens and like an open circuit immediately after. The relevant equations for RL circuits, particularly the formula for di/dt, are crucial for solving the problem. The user expresses confusion about the change in time and the application of Kirchhoff's Voltage Law (KVL) around the loops. They seek clarification on their approach and whether they are proceeding correctly with their calculations. Understanding the behavior of inductors during switch transitions is key to solving this circuit problem effectively.
vthokie11
Messages
3
Reaction score
0

Homework Statement


The switch in the circuit has been closed for a long time before opening at t = 0
a. Find i(t) across R3 for t>0.
b. Find i(t) across R2 for t>0.

I have attached the circuit.

Homework Equations





The Attempt at a Solution


The only thing I know for this problem is that when a switch has been in a certain state for a long time an inductor acts essentially like a wire (no resistance) and when the state changes the inductor has infinite resistance.
 

Attachments

  • HW7-1.jpg
    HW7-1.jpg
    10.2 KB · Views: 426
Physics news on Phys.org
To solve this you need to know the formula for di/dt for RL circuits. Isn't this in your textbook or covered by lecture?
 
I apologize...I thought that I included the relevant equations...but this is what I know:

hw7-eq.jpg


What I don't understand is what the change in time is...I really don't know how to go about solving this problem...and I have no examples from lecture...all I have from lecture is basically the 2 equations I have included. Any help would be greatly appreciated...Thanks.
 
So I've done some work and this is what I've came up with...I'm not sure if this is even remotely close:

I applied KVL's around each loop

HW7-KVL.jpg


HW7-KVLeq-1.jpg


Am I even on the right track with this?
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Why the need to be careful opening a switch on this RL circuit?
Replies
6
Views
916
RCL series circuit analysis: Damping Constant
Replies
1
Views
635
Potential Drop Across 15-mH Inductor at t=0?
Replies
5
Views
2K
Current through an inductor after a switch closes
Replies
4
Views
3K
RLC Circuit Analysis -- Two sources and two switches
Replies
3
Views
2K
Circuit with resistor, switch and capacitor
2
Replies
62
Views
5K
RL Parallel Circuit Behavior Upon Switch Closure
Replies
16
Views
2K
RC Circuit with parallel resistor
Replies
6
Views
3K
Voltage across switch in LR circuit as switch is opened?
Replies
1
Views
2K
Current of RC Circuit After Switch is Opened
Replies
3
Views
3K

Hot Threads

Recent Insights

Back
Top