Determine the voltage V

  • Thread starter Mosaness
  • Start date
  • #1
Mosaness
92
0
1. Determine the voltage v as labeled in Fig. 3.72, and calculate the power supplied by each current source.



Homework Equations



KVL and Ohms Law


The Attempt at a Solution



The first step is to try and simplify the circuit so that it gives a resistance of 0.75Ω, which is obtained by combining the two resistors that are in parallel: [itex]\frac{1}{1 + \frac{1}{3}} [/itex]. We thus now have a current dependent current source, 3ix, a current source of 2A and a resistor of 0.75Ω, with the total current flowing counterclock-wise.

Using this, KCL can be applied:

-3ix - 2 = 0 so that ix = -2/3

V is then:

(1)(-2/3) + (1)(-3)(-2/3) + (-2)(3) = -14/3


The power supplied by each current source then should be:

P(3ix) = (14/3)(2/3) = 28/9

P(2A) = (14/3)(-2) = -28/9
 

Attachments

  • Figure 3.72.png
    Figure 3.72.png
    6.5 KB · Views: 540
Last edited:

Answers and Replies

  • #2
ehild
Homework Helper
15,543
1,915
You assumed that the same current flows through both resistors which is not true. Use KCL for the node N to express i1 in terms of ix, and KVL for the blue loop in the attached picture.

ehild
 

Attachments

  • currentgen.JPG
    currentgen.JPG
    8.2 KB · Views: 511
  • #3
Mosaness
92
0
You assumed that the same current flows through both resistors which is not true. Use KCL for the node N to express i1 in terms of ix, and KVL for the blue loop in the attached picture.

ehild

Based on your diagram i1 = -ix.

As for the inner loops,

Do we combine the two resistors? They are in parallel after all and should give 0.75 ohms no?

And if we know that,

Then by KVL,

0.75(-3ix) -1.50 = 0 and we can solve for ix?
 
  • #4
Mosaness
92
0
Am I on the correct path?
 
  • #5
ehild
Homework Helper
15,543
1,915
Based on your diagram i1 = -ix.
NO, they are different. The loop is not a physical loop, only a closed path in the circuit, to get the sum of potential differences, which should be zero. How does the potential change across the 3 Ω and the 1 Ω resistors?


ehild
 

Suggested for: Determine the voltage V

  • Last Post
Replies
2
Views
745
  • Last Post
Replies
0
Views
2K
Replies
15
Views
3K
  • Last Post
Replies
8
Views
986
Replies
3
Views
3K
  • Last Post
Replies
4
Views
2K
Replies
6
Views
3K
  • Last Post
Replies
7
Views
2K
Replies
8
Views
11K
Top