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Finding current in a circuit using Kirchhoff voltage law

  1. Jul 25, 2015 #1
    1. The problem statement, all variables and given/known data
    Hi, I'm learning about Kirchhoff's laws, and have to solve the circuit. Attached picture of part the circuit I am attempting to solve. The ammeter reads 2 A.

    2. Relevant equations
    Kirchhoff's voltage law says the total voltage around a closed loop must be zero.

    3. The attempt at a solution
    By going around the loop I get 0 = -18V + (7 ohms)(I1) + (5 ohms)(2 A) + 3V.
    Then solving for the current I1 I find that it is -0.714 A. But in the solution it does not have a negative sign. What did I do wrong?
     

    Attached Files:

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  2. jcsd
  3. Jul 25, 2015 #2

    Nathanael

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    Homework Helper

    Algebra mistake? Your equation gives a positive value, +5/7

    But you did not even post the full circuit :\
     
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