I got this error, can someone help me please?

enter image description here

  • \$\begingroup\$ messy schematic ... D1 and D2 are not connected to R3 ... several other components are the same way ... the zig-zag above R5 is clutter ... C7 should be above R11 ... component labels at U2 are a mess \$\endgroup\$
    – jsotola
    Nov 17, 2022 at 18:42
  • 1
    \$\begingroup\$ You didn't follow directions: i.sstatic.net/TGZ0U.png \$\endgroup\$
    – Ste Kulov
    Nov 17, 2022 at 18:54
  • \$\begingroup\$ how would I? I literally have no idea whati should do \$\endgroup\$
    – Maya
    Nov 20, 2022 at 16:05

1 Answer 1


You forgot to add .lib opamp.sub to your schematic. Press S and type that, then press Enter, and then L-Click to place the SPICE directive. Alternatively, use [Opamps]/UniversalOpamp1 (no need for power supplies), or [Opamps]/UniversalOpamp2 or 3, 3a, 3b (which do need power supplies).

Additionally, you forgot to add a ground to V1, V2, value to C1 (that I can see, else is obscured by the message), you don't have a junction between D1, D2 and D3, D4, or C2, C3, C4. It looks like you're not using U2 as you should: you're using the power pins as inputs, and the inputs just connected through R5. And that LM324 is probably just the opamp2 renamed -- if so, it won't work that way, unless you're providing some sort of a .subckt, which had better have 3 pins only.

I would recommend stepping back and analyzing your goals, before asking for help. Also, your schematic is a bit of a spaghetti dish.

  • \$\begingroup\$ i need more details, how can I add .lib opamp.sub? it's my first time using LTSpice and I'm lost! \$\endgroup\$
    – Maya
    Nov 19, 2022 at 18:06
  • \$\begingroup\$ @MaryamElYaagoubi I've already told you what to do. It's quite literally the 2nd sentence in my answer. If you haven't bothered to read that far, what chances are there that you will even read the manual? (it's there precisely to help you) Which would also imply you haven't even read the part where I point out a few other mistakes... If you don't help yourself, nobody can force you. I certainly won't. \$\endgroup\$ Nov 19, 2022 at 20:40
  • \$\begingroup\$ I did read it, i just don't know where should I press the S and the other things! I'm illiteracy in this, and thank you so much for your help \$\endgroup\$
    – Maya
    Nov 20, 2022 at 16:02
  • \$\begingroup\$ It means press the S key on your keyboard, or go to the menu in "Edit > SPICE Directive". @Maryam , don't get me wrong, I wish you the best with your project but, this is not the way to go. Read a guide, a tutorial, the manual (the help file, press the F1 key) actually has this purpose, to help the users. This project is too complicated for someone doing this the first time. Learn the tool so that you'll know how to use it. Otherwise you'll have to stop at every step, ask, and wait for answers for hours or maybe days. If this is the only time you ewant to use LTspice, let someone else. \$\endgroup\$ Nov 20, 2022 at 16:08
  • \$\begingroup\$ thank you so much, it's my graduation project, and my professor imposed me to use LTSpice \$\endgroup\$
    – Maya
    Nov 20, 2022 at 21:22

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