I'm trying to simulate two scenarios in LTspice. One is when things are ok. The second is when a short happens. As you can imagine I'm a beginner with LTspice. At first I was just putting a resistor at the output of my circuit to simulate my load. And when I wanted to simulate the short, I put the resitor at 1 mohm.

But I'd like to "automate" this. A short that happens after the sim has been running for some time.

I tried this. But I don't have a perfect zero when shorted.

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But I've seen another solution:

enter image description here

When I do this I get the error : Can't find the definition model "SW".

EDIT: Thanks to Winny and his link I was able to correctly set up my short. You can also find more about switches in a post here

  • \$\begingroup\$ Hit F2, then look under the "Misc" folder and find "jumper." For a way to connect two different nodes, anyway. That may achieve what you want. Let me know, if not. \$\endgroup\$
    – jonk
    Apr 29, 2021 at 8:02
  • \$\begingroup\$ @jonk but the jumper doesn"t turn ON or OFF "alone"? \$\endgroup\$
    – Neeko
    Apr 29, 2021 at 8:05
  • 4
    \$\begingroup\$ For your switch problem, you need to add a spice directive as outlined here: analog.com/en/technical-articles/… and name your switch to the same as in the spice directive. \$\endgroup\$
    – winny
    Apr 29, 2021 at 8:06
  • 2
    \$\begingroup\$ @Neeko I was thinking you could just add it or remove it, running each time. Up to you. The other option is the voltage controlled switch you had trouble with. I was just trying to avoid writing up details on that. (I've written about it here, for example.) \$\endgroup\$
    – jonk
    Apr 29, 2021 at 8:14
  • \$\begingroup\$ @winny Thanks for the link. It was detailing at the end how to do a proper short with that switch. \$\endgroup\$
    – Neeko
    Apr 29, 2021 at 8:31


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