1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Find Vx using node voltage method

  1. Mar 20, 2017 #1
    Capture.PNG


    is= 1.2 mA

    i submitted my solution but it was wrong,can someone please explain why?

    /* i just wanted to check if my solution is correct so i don't lose marks on my homework
    did i do any mistakes ?
    if so please explain.*/
    my solution:
    IMG_20170320_221725.jpg
     
    Last edited: Mar 20, 2017
  2. jcsd
  3. Mar 20, 2017 #2

    CWatters

    User Avatar
    Science Advisor
    Homework Helper

    I haven't gone through all your working but check the polarity of the 30V source and the first term in the KCL equation.
     
  4. Mar 20, 2017 #3

    gneill

    User Avatar

    Staff: Mentor

    Hi Samira,

    Welcome to Physics Forums!

    In future be sure to use the homework formatting template that is provided in the edit window when a new thread is started here in a homework forum. It is one of the rules of the forums and you will find your posts deleted if it is not used.

    Regarding your question, your work and result look fine.
     
  5. Mar 20, 2017 #4
    alright, i'm sorry and thank you for your answer.
     
  6. Mar 21, 2017 #5

    CWatters

    User Avatar
    Science Advisor
    Homework Helper

    I still think the first term should be (Vx - (-30)) / 5

    For example to be consistent with the third term (Vx-(+80))/1
     
  7. Mar 21, 2017 #6

    gneill

    User Avatar

    Staff: Mentor

    Argh! You're right! I missed the reversed polarity on the 30 V supply o:) Good catch.

    @Samira : The first term in your node equation needs to be fixed. It should be ##\frac{V_x + 30}{5}## .
     
  8. Mar 21, 2017 #7
    i'm sorry i did not see your answer last night , i thought i only got one.
    thank you !
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted