A question about SPICE.

Discussion in 'Homework Help' started by interesting_dude, Sep 5, 2013.

  1. interesting_dude

    Thread Starter New Member

    Jul 28, 2013
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    0
    Hi all!

    Yesterday I've finished to read the DC-section of the theory book about electricity (in some places it was only a bit boring, but these explanation about thermocouples, about superconductivity, also about steering system and cart moving (who readed it knows about what I'm talking about :D) — are very exciting and non-standart, giving awesome understanding), but I need a small explanation please.

    [​IMG]

    Yeah, it may be a bit weird question, but: does that shunt resistor in-builded inside the SPICE programm (in transient-analysis function), or what? Where is it? I can't see it in netlist. :rolleyes:

    Link to the online version of the book: http://www.vias.org/feee/time_03.html
     
  2. WBahn

    Moderator

    Mar 31, 2012
    17,761
    4,800
    I don't like the use of the term "shunt" in this context. A "shunt" is something that bypasses something else, hence they are in parallel. Here the whole point is that the current through the resistor IS the current in the capacitor, hence they have to be in series.

    Your netlist has three components -- a voltage source (v1), a resistor (r1) and a capacitor (c1). The plot is the voltage from node 2 to node 0, (v(2,,0)) and the voltage from node 1 to node 2, (v(1,2)). The capacitor is connected between nodes 2 and 0, so the first one is the voltage across the capacitor. The resistor is connected between nodes 1 and 2, so voltage across the resistor is the second one. The voltage across the resistor is directly proportional to the current through the resistor, which IS the current through the capacitor.
     
  3. interesting_dude

    Thread Starter New Member

    Jul 28, 2013
    20
    0
    I understood it, thanks for clear explanation!
     
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