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Homework Help: Confused on amperes in primary & secondary circuits

  1. Apr 1, 2010 #1
    1. The problem statement, all variables and given/known data

    A transformer has 500 turns in its primary coil and 4000 turns in its secondary. (a) What will be the voltage in the secondary if the primary voltage is 110? (b) If 5 amperes flow through the secondary circuit of the transformer, what will the current in the primary be? (c) If there are 8 amperes in the secondary, how many are there in the primary?

    I'm a little confused on whether I'm inverting the equation correctly on parts b and c - can someone let me know if this is the formula they use?
    2. Relevant equations

    3. The attempt at a solution

    v2/v1=n2/n1 So V2/110=4000/500 = 880V

    b.)Ip/Is=Ns/Np = Ip/5 = 4000/500 = 40 A

    c.)Ip/Is=Ns/Np = Ip/8 = 4000/500 = 64 A
  2. jcsd
  3. Apr 1, 2010 #2


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    Staff: Mentor

    Looks correct to me.
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