How can I .MEASURE at what input voltage a certain current occurs when doing a DC sweep in LTSpice?

For instance, consider the following situation:

I was hoping to find the voltage that generates a base current of \$200\mu\text{A}\$ by using FIND ... WHEN as shown in the image, but I only get Measurement "ub" FAIL'ed. (I guess the syntax is not applicable to DC sweeps?)

  • 4
    \$\begingroup\$ Why can't you just plot Vbe against Ib instead and look at the resulting graph? \$\endgroup\$
    – Andy aka
    Commented Dec 17, 2021 at 13:44
  • \$\begingroup\$ Ib(Q1) never gets to be 200u given your setup; try 20u. You could have found this out for yourself if you had actually plotted the waveforms. \$\endgroup\$ Commented Dec 17, 2021 at 15:07

1 Answer 1


Here is the command to measure it when you eventually get it to 200uA.

enter image description here

Another variation with respect to the sweep variable:

enter image description here


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