Help finding error in my Circuit Analysis

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
3 replies · 2K views
mkematt96
Messages
25
Reaction score
0

Homework Statement


IMG_1013.JPG


Homework Equations

The Attempt at a Solution


IMG_1012.JPG


My values for i1,i2,and i3 were: -.005179,-.002857 and .004857. When I ran the same circuit through LT Spice the values they gave me were .00059081,.000809628, and .00119037. Where did I make my error?
* as a side not I notices I only have 1000 instead of 10,000 in my matrix for the first line. The values I got were using 10,000 instead of 1000 in the first line.
 

Attachments

  • IMG_1013.JPG
    IMG_1013.JPG
    46.7 KB · Views: 862
  • IMG_1012.JPG
    IMG_1012.JPG
    50.7 KB · Views: 840
Physics news on Phys.org
Since you know the answer from your simulation result, I'd post the values I am getting.
I am getting VAB= 7.221V and IR3= 1.4mA.

For I1, I2 and I3 (labelled differently in my working) I am getting the same values as your LTspice result (just 10 times more, since you used 10000 instead of 1000).
 
  • Like
Likes   Reactions: berkeman
I see a couple of mistakes. In your equation for loop 1 you left out the 5k resistor.

In your equation for the super mesh, you have a term 4k(I1 - I2). This should be 4k(I2 - I1).
 
The Electrician said:
I see a couple of mistakes. In your equation for loop 1 you left out the 5k resistor.

In your equation for the super mesh, you have a term 4k(I1 - I2). This should be 4k(I2 - I1).
After making these changes I got my numbers to match the LT Spice number! Thanks!