Use Node Voltage Analysis

  • Thread starter jdawg
  • Start date
  • #1
367
2

Homework Statement


Find V1. I attached a picture for the circuit.

Homework Equations




The Attempt at a Solution


This is what I did (Refer to Fig. 1):

-2A + (V1)/(50) +(V1-45)/(1) = 0

But when I looked at the solution my professor posted this is what he did (Redrew Fig.1 as Fig.2):

-2A + (V1)/(50) +(V1-45)/(1+4) = 0

I thought you were finding the potential difference between V1 and the voltage source? I don't understand why he included the 4Ω resistor. Any help is appreciated!
 

Attachments

  • Circuit2.pdf
    232 KB · Views: 114

Answers and Replies

  • #2
gneill
Mentor
20,925
2,866
Each term of a node equation represents a branch current. A branch is a series-connected set of components lying between two nodes. The current flows through the entire branch. For the branch in question there are two resistors and one voltage supply stretching between node V1 and the reference node.

Edit: I should mention that rearranging the components in a series circuit does not change the current or end-to-end potential drop. It's like rearranging the terms of a sum of terms in math; they add up to the same value no matter the order.
 
  • #3
367
2
Thanks for clearing that up!
 

Related Threads on Use Node Voltage Analysis

  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
2
Views
638
  • Last Post
Replies
5
Views
749
  • Last Post
Replies
2
Views
965
  • Last Post
Replies
1
Views
667
  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
6
Views
2K
Replies
1
Views
840
Replies
4
Views
869
Replies
4
Views
4K
Top