Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Prove of thevenin law question

  1. Dec 3, 2009 #1
    here is how my prof taught me :
    there is a system pi which is connected to a ressistor.
    we replace the resistor with a current source
    so the current which flows threw the ressistor did not change
    and by some other law so does the voltage do not change on that branch.

    and we replace every intial condition
    which differs zero with independant source(capacitator which have v(t=0)=5 for example into capacitator v(t=0)=0 and voltage source 5volts)

    now comes the problematic part
    "we dissconeect the current source so we have Voc between those two points
    from system pi,and then we turn every independant source in the pi system into 0
    current source gets 0 current (open circuit)
    voltage source is short circuit.

    and we get some other voltage coming out of the pi system

    and so by the super position law we sum them to gether and get thevenin law.

    question 1:
    when i hear superposition law i imagine a circuit which has two voltage sources
    and we dissconnect one of the source and calculate what current flows on some ressitor

    then we reverse the situation and we calculate again the current
    and then we sum both currents
    both half coexyst together.

    the problem is that in my profs prove
    there is no two coexysting parts

    we have once voltage from pi
    and the other votage from pi when all the intependant sources are zero

    there is no super postion because those two situations are not on the same time

    2.if we turn every initial condition differs zero into independant source
    then when we turn every source to zero then there is no voltage at all

  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted

Similar Discussions: Prove of thevenin law question
  1. Lenz's Law Question (Replies: 19)