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Homework Help: Effective resistance of secondary circuit in transformers

  1. Aug 4, 2010 #1
    1. The problem statement, all variables and given/known data
    You need a transformer to reduce a voltage of 150 V in the primary circuit to 25 V in the secondary circuit. The primary circuit has 130 windings and the secondary circuit is completed through a 55 ? resistor. (a) How many windings should the secondary circuit contain? (b) What is the effective resistance of the secondary circuit?

    2. Relevant equations


    Reff= R(N1/N2)^2

    3. The attempt at a solution

    I solved part A. N2 is 22 windings. However, part B is 1500 but I can't seem to get that answer! I used the above equation but it doesn't give me that answer. Is the Reff equation that I'm using wrong? Please help me!
  2. jcsd
  3. Aug 4, 2010 #2
    i think you got the secondary circuit voltage and windings also. ya its correct secondary circuit resistance is depend on load only.
  4. Aug 4, 2010 #3
    Yes, but if I plug in the values with that equation I don't get 1500 for part B. I don't know what I'm doing wrong.
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