1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: RLC cricuit

  1. May 21, 2017 #1
    1. The problem statement, all variables and given/known data
    what is the value combined impedance of the parallel circuit ?when R=25 ,X[c]=100 and X[L]=25

    2. Relevant equations
    I think we use this equation to solve parallel impedance .... acp176.gif .

    3. The attempt at a solution
    z=1/√((squ(1/25))+(squ((1/25)-(1/100))))=1/√(1/625)+squ(3/100)=√10000/25=100/5=20
    but the ans is given is 120 what I do ???
     
  2. jcsd
  3. May 21, 2017 #2
    Hi,
    with your value(R=25,XL=25,XC=100) and your equation you found the right answer. Maybe you forget to convert L and C value to phasor form, it means ( XL=JwL not XL= L) or the book answer is wrong
     
  4. May 21, 2017 #3
    no its is given the value of Xc and XL ......... no need to find Xc and XL
    vetre
     
  5. May 21, 2017 #4

    cnh1995

    User Avatar
    Homework Helper
    Gold Member

    Perhaps it is a typo. The answer is j20, not 120.
    The equivalent impedance of a bunch of parallel impedances is less than the least of them, which means the answer is less than 25.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted