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Homework Help: A transformer problem

  1. Oct 13, 2005 #1
    Hi,

    My Question:

    A model train transformer plugs into 120-V ac and draws 0.35A while supplying 7.5A to the train. (a)What voltage is present across the tracks? (b) is the transformer step-up or step down?

    Work

    Part A:

    I'V'=I"V"
    (0.25A)(120V)=(7.5A)(V")
    ((0.25A)(120V))/(7.5A)=V"
    V"=5.6V

    Part B:

    Step-down, because the secondary voltage is lower than the primary voltage.

    Is it correct:confused:

    Thank You:smile:
     
  2. jcsd
  3. Oct 14, 2005 #2

    Doc Al

    User Avatar

    Staff: Mentor

    You are correct. (Note typo in your part A equations: you wrote "0.25A" instead of "0.35A".)
     
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