Need help with circuit simulator

Discussion in 'General Electronics Chat' started by eestlane1991, May 15, 2011.

  1. eestlane1991

    Thread Starter New Member

    May 15, 2011
    4
    0
    Hi,
    i have to make an logic schema in Circuit Simulator.
    http://www.falstad.com/circuit/
    Using CMOS and and realise the function on transistor level.
    The function is :
    [​IMG]

    Could someone make it for me?
     
  2. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,670
    804
    God, why would you want to do that?
    Get Microcap or LTSpice or something, this java applet is nice to get some idea how things work, but certainly bad for getting the real results.
     
  3. eestlane1991

    Thread Starter New Member

    May 15, 2011
    4
    0
    I don't know really much about the simulators it's the one my teacher told to use.
    I just need the schema.
     
  4. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,670
    804
    You didn´t say what the C pin does. Anyway, open the NOR schema in the simulator and go from there.
    It´s in cirtuits - logic families - cmos - cmos nor
     
  5. rapidcoder

    Member

    Jan 16, 2011
    37
    3
    Oh'rly? I thought getting non-real results is a property of ALL circuit simulators. You get just some approximation. I've seen terribly inaccurate, useless traces from LTSpice and TINA, so judging Falstad's simulator only by its low model accuracy is not fair. Actually many engineers prefer more accurate and stable engine (like in NL5 for example) and simplified models, than the other way round. Getting slightly less accurate result is usually much better than getting no result at all, because of e.g. "timestep too small" problem, so common to all SPICE-based simulators.

    A short comparison of Falstad's simulator and LTSpice:

    Runs on ChromeOS: Falstad's - yes; LTSpice - no
    Runs on *BSD, Solaris, Linux: Falstad's - yes; LTSpice - no
    Time to install and run: Falstad's: no installation required; LTSpice - a few minutes, admin rights required
    Interactive simulation: Falstad's - yes; LTSpice - no
    Current flow visualization: Falstad's - yes; LTSpice - no
    Crappy schematic editor GUI: Falstad's - yes; LTSpice - yes
    Huge model library: Falstad's - no; LTSpice - mostly Linear Tech models only
    Numerical instabilities and convergence problems: Falstad's - very common; LTSpice - common
    Model accuracy: Falstad's - low; LTSpice - good; but that doesn't really matter that much because of problems mentioned in the previous point
     
    Last edited: May 16, 2011
  6. eestlane1991

    Thread Starter New Member

    May 15, 2011
    4
    0
  7. eestlane1991

    Thread Starter New Member

    May 15, 2011
    4
    0
  8. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,670
    804
    oh, now Im getting some idea what it should do..
    Should it be edge or level triggered?
    If you want it to be edge triggered, use the circuit here, the second picture from bottom. http://www.labri.fr/perso/strandh/Teaching/AMP/Common/Strandh-Tutorial/flip-flops.html I think the invertor on the left is not needed in a sr-latch.

    If it should be just level triggered, ommit also the right half of the circuit, basically leaving just the and gates.
     
    eestlane1991 likes this.
Loading...