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Homework Help: Analyzing Simple Circuits

  1. Aug 27, 2013 #1
    1. The problem statement, all variables and given/known data
    Hello! I'm having difficulty analyzing this circuit and determining the currents I1,I2,I3.

    2. Relevant equations
    Ohm's Law
    Kirchoffs Laws
    Current and Volatage divider

    3. The attempt at a solution
    So far all I can manage is simplifying the circuit, Im sure im suppose to use current or voltage divider I just can't work out where.

    Using software simulation the values should be around ....I1=0.5404, I2=0.8109, I3= -0.2702mA

    Any help on which rules and where to apply them would be much appreciated!

  2. jcsd
  3. Aug 27, 2013 #2


    User Avatar

    Staff: Mentor

    Your simplified circuit is correct except you have a typo for the left resistor. Should be kOhms, not Ohms.

    In problems like this, I prefer to write the KCL equations, and just solve them simultaneously. That's the most intuitive technique for me, and almost always works without modification.

    So this is a pretty simple circuit -- call the voltage at the top node V1, and write the one KCL equation for that node. You can then solve for that voltage, which lets you solve for the 3 currents that the problem is asking for. In problems with multiple nodes, just write the KCL equations for each node and solve the equations simultaneously.

    I prefer to write the KCL equation(s) as the sum of all the currents out of each node equal zero.

    Can you show us your work given those hints?
  4. Aug 28, 2013 #3
    Ahh thankyou very much. I was messing around with equations I didn't need. I just wrote out the Ohms, KCL & KVL equations then solved simultaneously, came out perfect.

    Once again, thanks :)
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