OpAmp virtual/relative ground - proper use

Discussion in 'Analog & Mixed-Signal Design' started by ci139, Aug 21, 2016.

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  1. ci139

    Thread Starter Member

    Jul 11, 2016
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    new thread title : a virtual tool for evaluating the Spice Op.-Amp. models (see figure just below)

    LM324A - Test - Std-0200.png

    if there is no problems /* it is used to test **OpAmp-X's the "I/O and other zeros(signal grounds)" + unity gain -- for it's** apx./general "behaviour" */ then don't respond -- (the OpAmp-s' biasing on this figure is intuitive - to avoid some models to cause "timestep too small" error - and perhaps not fully consistent)
    i however welcome all suggestions to make this virtual test tool more practical
    (edited 2016.08.22 15:40 UTC)
     
    Last edited: Aug 22, 2016
  2. ci139

    Thread Starter Member

    Jul 11, 2016
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    note: just provided as an example of how to simulate "custom models" in spice (the zip attachment -- the component model name attr.Value = model name - that is a .SUBCKT model name in .cir file , but reference to model - .cir file - is .include filename.cir)
    zzz_White-LED_Flasher_4x_PZ-v2a.png
    ▲ an off the shelf model (some 10y old) -- moisture proof metal casing -- replaced the power switch (® weared off) -- modified case/grnd-PCB contact -- compact size (there are lot of plusses that weight out it's avg. design)
    zzz_White-LED_Flasher_4x_PZ-v2cc.png
    (usually the Op.Amp.s' macro models "don't like" complex and/or switching applications -- here it amazingly/so far works)
    concep design that likey won't fit into the casing of above -- PPM - adjustable from R7 (to GND) only -- attempted a fixed current/luminosity v. (TLS2361 based) trying to keep the component count minimal -- would be likely better all in one chip -- this likely stays a theoretical concept
    ((↑↑ about trg. app.))
     
    Last edited: Aug 22, 2016
  3. Papabravo

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    Feb 24, 2006
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    Deciphering Hieroglyphics seems the a walk in the park by comparison to that hot mess you posted.
     
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  4. crutschow

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    Is this a bad machine translation from a different language? :confused:
    That's rather what it reads like.
     
  5. AnalogKid

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    Aug 1, 2013
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    Where are you located, and what is your question?

    ak
     
  6. ci139

    Thread Starter Member

    Jul 11, 2016
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    -- thanks for feedback , gonna be useful for adjusting my world iterface module e.g. i gonna learn egytian and post it in a series of ducks and feathers ?
    -- Eesti (borderline center @ 58º41'25.525"N 24º50'47.100"E) , ?.1 the U1 refers it's output "vG" and "random offset" both to a "physical ground" - where the ideal input ground is - ?.2 the U2 refers a signal input "vG" and a " physical ground " both to a "virtual ground" - (i don't remember why exactly such setup - this time i needed to confirm the datasheet's GBW 7MHz = Model's GBW 6MHz)
    vG.Z @ oo=416.6162816µ , vG = 0
    pxt.Z @ oo = -2.19230973025 , vG = -1.63850915432 , pxt = 0
    **** ??? how to i get ↑↑those↑↑ grounds correct - or - ??? are they correct - coz the actual INP.GND<>OUTP.GND<>ideal.GND=(Ucc+Uee)/2

    as i said i dont remember why the U2 reffers the input as it does (i have done a lot of other stuff while i last evaluated my custom LM324 models - it gave right results there . . . which i don't remember what they were or how they were) . . . say vG=GND and Ri>>Rii -- ">>" = "is much grater than" -- gives us a near K.u inverting amplification for input signal "pin" . . . ??? as i said i don't remember - so (better to go back to ****)

    if you don't see anything wrong or don't see anything (includes "wrong") - then likely there is nothing to suggest.;):oops: - so - ignore this post -- it's nothing critical nor urgent o_O
     
  7. AnalogKid

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    Aug 1, 2013
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    I don't see anything right.

    There are many symbols that are a triangle pointed left or right. Since these can *not* be ground symbols (all ground symbols point down), what are they?

    The output of U1 has a 100 uF capacitor. No matter what you think U1 is doing, it is not doing that. The circuit cannot work.

    One part of the schematic has the phrase "1 Hz (divided by) 10 GHz". What does this mean?

    And, again, why are you posting this circuit? If you have a question about its performance, can you say what that question is?

    ak
     
  8. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    I've tried, but failed, to understand the point of this thread :confused:.
     
  9. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    A ground symbol in LTspice will be pointing to side when you place it on a horizontal wire. (not that it helps me understand anything)
     
  10. AnalogKid

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    Grounds point downward. That the program lets you use the symbol incorrectly is not an excuse.

    Rigid? Rarely. About this? Always.

    ak
     
  11. OBW0549

    Well-Known Member

    Mar 2, 2015
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    It seems to me that this stuff is most likely what is referred to as word salad.
     
  12. ci139

    Thread Starter Member

    Jul 11, 2016
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    Try again !
    One part of the schematic has the phrase "1 Hz (up to) 10 GHz". This means the observed frequency spectrum.
    What else there could be OR what there should be different -- to verify model against the main parameters on the datasheet?
     
  13. ci139

    Thread Starter Member

    Jul 11, 2016
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    you eighter do something or then you don't e.g. find excuses for why you shouldn't . . .

    i suggest do something - you don't have to find excuses for not doing it

    if you find this thread inappropriate - remove it . . . it seems i can do my stuff faster on my own ;)
     
  14. crutschow

    Expert

    Mar 14, 2008
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    If so, then you thought process much be a lot more coherent than your writing. :rolleyes:
     
  15. DickCappels

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    Aug 21, 2008
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    Per request by Thread Starter, this thread is closed for business.
     
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