Inserting coupled inductors into NG-Spice’s netlists graphically.

I have spent quite a few postings, describing how the Open-Source circuit simulation programs “NG-Spice”, belonging to the “gEDA” suite, can be used. And one of the facts about them which I’ve recognized, is that they essentially come as three programs: The (non-GUI) engine which simulates Netlists; ‘gschem’, a graphical program which allows schematics and custom symbols to be edited; a third (GUI-based) program, ‘GSpiceUI’, that can import the schematic and export the netlist of a simulation to be run, as well as run the simulations.

What the first two programs do, isn’t always well-matched. ‘gschem’ can create schematics, with no regard for the fact that the Spice engine can’t simulate all the components.

But, One capability which NG-Spice has at the level of Netlists is, to simulate “coupled inductors”, which are denoted by a ‘RefDes’ which begins with the letter ‘K’.

Why is this potentially useful? Because, if the user simply puts the standard, library transformer, what NG-Spice will simulate, is a perfect transformer, which behaves as well at 60Hz, as it does at 60MHz. The user would have no way to specify any of that transformer’s parameters, then. It’s often more useful to simulate components, with built-in parasitic flaws, such as, coupling constants that are 0.99 or 0.9 instead of 1.0…

It would be nice, just to be able to drop such a coupling into a ‘gschem’ schematic, and have ‘GSpiceUI’ create its simulation ‘the easy way, via the GUI’.

Well, that can be prepared. And, the way to prepare it is, using ‘gschem’ in order to define a custom symbol…

 

coupled-inductors-1

 

(Updated 6/09/2021, 16h35… )

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