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LTspice not sure about error "vout missing node".

  • \$\begingroup\$ What does the error say? \$\endgroup\$
    – Hearth
    Oct 21, 2022 at 1:08
  • \$\begingroup\$ vout missing node \$\endgroup\$ Oct 21, 2022 at 1:09
  • 3
    \$\begingroup\$ It looks like you've missed the + input of the op amp, for one thing. I'm confused at how your port label looks, also; is there perhaps a space or two before Vout? (e.g. " Vout" as the name instead of "Vout") \$\endgroup\$
    – Hearth
    Oct 21, 2022 at 1:14
  • 1
    \$\begingroup\$ Those blue square dots on U1 and the Vout label shouldn’t be there. Those are an indication that you overlapped some wires. Vout label should have no spaces as Hearth said. Your schematic should look just like the one you are copying. \$\endgroup\$
    – GodJihyo
    Oct 21, 2022 at 1:32
  • 2
    \$\begingroup\$ @플랑드레 Hearth has the right of it. You completely missed connecting the wire to the (+) input. Just look at how it looks near the (-) input. There's no tiny box there, right? That's because a wire did get attached there. But the little box is still there near the (+) input. That means you missed it. \$\endgroup\$
    – jonk
    Oct 21, 2022 at 2:00

1 Answer 1


Check the netlist (view=> spice netlist ). Check u1, it should have 5 nodes connected, vp vn vout gnd (also known as 0) and vpp (not nessacerrilly in the order)

If the nodes aren't listed they need to be connected, also, vout needs a load (a 1meg ohm resistor would work)

  • \$\begingroup\$ i read your comment and i checked it there is no gnd i still have no idea about how to fix it from here... \$\endgroup\$ Oct 21, 2022 at 1:22
  • \$\begingroup\$ You have two nodes that are not connected, you need to know how LT spice works, spend some time learning how it generates a netlist file (that's what you should check when you get an error) You sould be able to write a netlist file. \$\endgroup\$
    – Voltage Spike
    Oct 21, 2022 at 4:57
  • 2
    \$\begingroup\$ @VoltageSpike The output resistance is not mandatory but, OP did miss the connection to the non-inverting input. The longer wire at the power pins can be forgiven. \$\endgroup\$ Oct 21, 2022 at 7:31
  • \$\begingroup\$ I usually put loads on to make the simulation go better \$\endgroup\$
    – Voltage Spike
    Oct 21, 2022 at 17:16

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