Ideal transformer

[bnilsson11]

Sometimes an ideal transformer could be useful, e.g. when modelling mechanical devices with properties that should be transferred to electrical. Is there such a device in the qucs-s toolbox?

[ra3xdh]

SPICE doesn't support such device. Only coupled inductors are available for SPICE. The ideal transformer is available only for Qucsator backend:

[bnilsson11]

Can any of the transformers in the Library be tweaked to be closer "ideal" when using it for impedance transformation?

[tomhajjar]

The LTspice guys have created countless transformer models. Most can be used to make a subcircuit in Qucs-S with ngspice.

You can certainly find one that meets your expectations for an "ideal" transformer.

Transformers.zip

[felix-salfelder]

SPICE doesn't support such device.

Please explain why. I suspect that it does.

I once found [1]. "Works like a charm" according to [2]. Ancient Gnucsator [3] has the following.

module Tr (outp, inp, inn, outn);
  parameter T=1.;
  CCCS #(.gain(T)) v(outp_, inp, inn, outp);
  vcvs #(.gain(T) e(outp_, outn, inp, inn);
endmodule

Here's an exercise: Why is this hard to read? Improve the representation: Rename the nets, add port names, and group the connections to reflect common sense. Compare with representations in other languages. Bonus points: send a patch.

[1] https://forum.kicad.info/t/solved-transformer-models-in-simulation/10592
[2] https://maker.pro/forums/threads/spice-ideal-transformer.75739/
[3] https://codeberg.org/gnucap/gnucsator/src/branch/develop/include/lumped.v