How to use a nutmeg equation to set a parameter?

[Swontu]

Hi there,

can someone explain to me what I'm doing wrong in this trivial toy example, when using an Nutmeg equation to set a parameter?

Interestingly, if I change the simulator to SpiceOus and insert an equation, qucs-s inserts a regular equation (not Nutmeg). Now when I change back to the ngspice-simulator, the simulation runs without an error and the plot shows the expected result:

The netlist now also includes a .PARAM statement, which was missing before:

My setup:
Windows 10
ngspice-42
Qucs-S Portable 24.1.0

Thanks in advance for any help!

[ra3xdh]

can someone explain to me what I'm doing wrong in this trivial toy example, when using an Nutmeg equation to set a parameter?

Nutmeg is SPICE postprocessor. These equations are evaluated before simulation. You cannot substitute parameters using Nutneg equations. Use .PARAM instead. This device could be found in equations group.

qucs-s inserts a regular equation (not Nutmeg).

It is qucsator equation. It supports only limited set of mathematical functions that are compatible between all simulators. I am hiding it in SPICE mode to prevent its insertion by accident.