Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Weird Transformer Problem

  1. Aug 1, 2010 #1
    Weird Transformer Problem :(

    1. The problem statement, all variables and given/known data

    "In the transformer shown in the figure below, the load resistance RL is 44.0 Ω. The turns ratio N1/N2 is 2.10, and the rms source voltage is ΔVS = 77.0 V. If a voltmeter across the load resistance measures an rms voltage of 26.5 V, what is the source resistance Rs?"


    2. Relevant equations

    See attachment for Equation of Rs


    3. The attempt at a solution

    I plugged in my values for the formula i got for Rs but got it wrong? I got 77.4 Ohms

    Does anybody know what i'm doing wrong? Because i sure don't.

    Any help will be greatly appreciated, thanks in advance!

  2. jcsd
  3. Aug 2, 2010 #2

    Andrew Mason

    User Avatar
    Science Advisor
    Homework Helper

    Re: Weird Transformer Problem :(

    How are you analysing the problem?

    Can you determine the voltage drop across the source resistance? Can you determine the power in the secondary coil? How is that related to the power passing through the primary coil?

  4. Aug 3, 2010 #3
    Re: Weird Transformer Problem :(

    Wow, you were absolutely right, i did it through power like you instructed and it worked like a charm.. I also learned not to round too soon into the problem.. :/

    Thank you!!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook