This site is using CircuitLab. In some SPICE programs it is possible to simulate CM choke. For example:

Mutual Inductance is designated in a SPICE netlist by beginning the first word (label) of a new line with the letter "K". It is unique among the basic circuit elements in LTspice in that a schematic symbol is not used to represented it.

Is there a way to achieve this by using CircuitLab?

  • \$\begingroup\$ Is it even possible? \$\endgroup\$ – pnatk Dec 21 '18 at 17:40
  • \$\begingroup\$ You could use a pair of voltage-controlled-voltage-sources (VCVS) in series with inductors but it is clumsy. circuitlab.com/forums/modeling-and-simulation/topic/75exru43/… Spice or Falstad Simulator it is far easier to define coupling ratio. \$\endgroup\$ – Tony Stewart EE75 Dec 21 '18 at 17:55
  • \$\begingroup\$ @TonyEErocketscientist This CircuitLab is very limited. \$\endgroup\$ – pnatk Dec 21 '18 at 18:01
  • \$\begingroup\$ that's why I refuse to use it for simulation \$\endgroup\$ – Tony Stewart EE75 Dec 21 '18 at 18:44

(CircuitLab simulation engine author here -- just noticed this question!)
CircuitLab does support coupled inductors. Define a Parameter Element with a name like "K L1 L2". For example:


simulate this circuit – Schematic created using CircuitLab

(Example adapted from: https://web.cecs.pdx.edu/~tymerski/ece222/How%20to%20create%20a%20transformer%20using%20LTSpice.pdf)

It can also handle multiple inductors, and you can even do parameter sweeps over the coupling coefficient, for example:


simulate this circuit

(Example adapted from: https://web.cecs.pdx.edu/~tymerski/ece222/How%20to%20create%20a%20transformer%20using%20LTSpice.pdf)

Lp, Ls1, Ls2 effectively form a center-tapped transformer. If you run the simulation, this second example shows a parameter sweep which allows you to compare the results for different values of the coupling coefficient.


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