HELP: Dependent Source [circuit decoupling]?

Discussion in 'Homework Help' started by kougou, Oct 13, 2013.

  1. kougou

    Thread Starter New Member

    Oct 20, 2012
    8
    0
    Hi all

    I have question about the voltage control current source that looks like the diagram below. w.png

    Why the current source decouples the leftmost resistor from receiving power from the main circuit?
     
  2. WBahn

    Moderator

    Mar 31, 2012
    17,720
    4,788
    The answer lies in understanding what a current source does. It ensures that a given current flows through it regardless of the voltage across it. Said another way, it will produce whatever voltage is needed across it in order to maintain the given current through it. So there is no change you could make to the right of the circuit that will affect the current through the current current source (ideally, even open circuiting it wouldn't do it because then the current source would produce so much voltage as to route the electrons through the nearest galaxy, if that's what it took).

    The same thing is true with a voltage source. When you plug loads into the wall outlet at home, you are putting them in parallel with each other and with a voltage source. You don't expect that plugging in your shaver will be noticeable by the person using a reading lamp in the next room. Why not? Because a voltage source isolates parallel circuits by establishing a fixed voltage difference on the nodes they share and producing whatever current is needed to make that happen.
     
    anhnha likes this.
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