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Homework Help: Transforming a switch into a voltage source

  1. Jan 19, 2010 #1
  2. jcsd
  3. Jan 19, 2010 #2

    berkeman

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    Staff: Mentor

    What is that thing? A 12uV voltage source backwards? Or is it supposed to represent the final current through the inductor?
     
  4. Jan 19, 2010 #3
    its some step function
    which represents a voltage sorse
    -t says its zero from t>0 and forward
     
  5. Jan 19, 2010 #4

    berkeman

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    Staff: Mentor

    Oh, so it's meant to replace the switch with a step function. Okay.
     
  6. Jan 19, 2010 #5
    its acts like a switch
    its a step function of -t

    from t>0 and forward it goes to zero like a switch

    but how they got its coefficient of the step function?

    i cant see how its the same as the original circuit
    ??
     
  7. Jan 19, 2010 #6

    berkeman

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    Staff: Mentor

    It looks to me like it generates a 12V that is opposing the other 12V supply, up until t=0 when it goes off and lets the other 12V supply be the only supply in the circuit. for t<0 when the two 12V supplies oppose each other, there is no net voltage to drive a current around the circuit.
     
  8. Jan 19, 2010 #7
    can you describe how its like the original circuit?
     
  9. Jan 20, 2010 #8
    how its opposing ??

    its plus 12
    not minus 12
     
  10. Jan 20, 2010 #9
    ahh thanks :)
     
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