LTSpice LM741 Problem

Discussion in 'General Electronics Chat' started by sdas86, Apr 19, 2015.

  1. sdas86

    Thread Starter New Member

    Mar 18, 2015
    26
    0
  2. ericgibbs

    Senior Member

    Jan 29, 2010
    2,499
    380
    hi,
    I would suggest that you use Start/Search/Files and Folders from the windows lower menu bar, for LM741.* , search the LTSpice main folder for all occurrences of LM741.
    Make sure that you have the LM741 extensions in the required folders.
    E
     
  3. sdas86

    Thread Starter New Member

    Mar 18, 2015
    26
    0
    Hi,
    My symbol is placed at D:\LTC\LTspiceIV\lib\sym\BEE215
    The folder name is BEE215.

    I have 3 items in this folder: LM741.asy, LM741.MOD and LM741.lib

    May I know how to save the .lib properly? Do I need to open the .mod using Notepad and then save as .lib?
     
  4. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,767
    1,102
    Leave the .asy file as is, but move the .mod and .lib files to the ...\LTspiceIV\lib\sub folder. Don't forget to use the ".include LM741.mod" or ".include LM741.lib" directive on your schematic.
     
  5. crutschow

    Expert

    Mar 14, 2008
    12,977
    3,221
    Did you close and restart LTspice?

    Edit: If you put the .asy file in the lib/sym/Opamps directory and the .lib file in the lib/sub directory then the 741 opamp should appear in the Opamps library in LTspice which can be directly used without requiring any ".include" command, the same as any other opamp.
     
    Last edited: Apr 19, 2015
  6. sdas86

    Thread Starter New Member

    Mar 18, 2015
    26
    0
    Hi,
    I do not understand. The .asy file is a symbol file. This .asy file I copied from the opamps2.
    I open a folder called BEE215. I put this LM741.asy, LM741.lib and LM741.mod into this BEE215 folder. Am I doing this wrongly?

    But after it is added, I went into LTSpice and press F2 and add. but nothing appear.

    Thanks
     
  7. sdas86

    Thread Starter New Member

    Mar 18, 2015
    26
    0
    Hi All,
    Now since I have LM741.lib and LM741.mod.
    Can I just copy the Opamps2.asy?
    I open Opamps2.asy in LTSpice and I edit the Attributes (Edit > Attributes > Edit Attributes).
    Spice Model: \sym\BEE215\LM741.mod < Do I need to put in full path link like D:\LTSpice.......\LM741.mod ?
    Modal File: \sym\BEE215\LM741.lib < Do I need to put in full path link like D:\LTSpice.......\LM741.lib ?

    And then I save this as Opamps-LM741.asy. Can I do it this method?
     
  8. crutschow

    Expert

    Mar 14, 2008
    12,977
    3,221
    Your method isn't necessarily "wrong". I just suggested an alternate way which allows normal access to the 741, the same as all other op amps, and doesn't require the addition of a new folder.

    Did you close LTspice and restart it after adding the files?
     
  9. Veracohr

    Well-Known Member

    Jan 3, 2011
    549
    75
    You don't really need a dedicated symbol for the 741, just add opamp2 to your design and rename it LM741, then add ".include LM741.lib".
     
  10. eetech00

    Active Member

    Jun 8, 2013
    644
    110
    To avoid any confusion, you don't really "rename" it.
    Change the "opamp2" attribute value to the name contained in the LM741.lib file that identifies the LM741 subcircuit.
    For example, if the subcircuit statement is ".subckt LM741A 1 2 3 4 5 6 7 8", change the value to "LM741A", without the double quotes. In addition, the number of pins defined by the .subckt statement needs to match the number of pins on the symbol. In my example, there are 8 pins, so the opamp2 won't work and will produce errors because it only has 5 pins.

    eT
     
  11. Veracohr

    Well-Known Member

    Jan 3, 2011
    549
    75
    OK that's true, but is there a LM741 spice model that has 8 pins? If not you've only introduced a needless hypothetical to confuse the question at hand.
     
  12. ScottWang

    Moderator

    Aug 23, 2012
    4,850
    767
    Is this a homework?
     
  13. eetech00

    Active Member

    Jun 8, 2013
    644
    110
    I don't know that there is or that there isn't. Neither do you.:cool:

    This device has seven pins and one NC.
    http://www.ti.com/lit/ds/symlink/lm741.pdf

    The point is...the number of symbol pins vs .subckt pins have to match.
     
    Last edited: Apr 23, 2015
  14. sdas86

    Thread Starter New Member

    Mar 18, 2015
    26
    0
    Hi, This is not my homework but my own hobby and also my job. I want to know how to add extra components to LTSpice but somehow not working.
     
  15. ericgibbs

    Senior Member

    Jan 29, 2010
    2,499
    380
    Hi,
    Unzip this LM741 zip and give it a try, note the text 'how too' file.
    E
     
  16. ScottWang

    Moderator

    Aug 23, 2012
    4,850
    767
    Then what's your application circuit?
    When you using this old op amp then you will need a little skill.
     
Loading...