This is a complex request! I want a controllable animation of a transformer, in the style of Walter Fendt's animations (eg http://www.walter-fendt.de/ph14e/generator_e.htm).
Requirements are: live plot of primary and secondary voltages along with animated B-field lines showing: (a) how the core links the field from the primary to the secondary coil; (b) how the B-field lines are "cut" by the turns of the secondary coil as they "come in from infinity" during a increasing field strength time (and also when they "rush out to infinity" during a decreasing field strength time) thus inducing the secondary voltage according to this statement of Faraday's Law: "... the induced emf being proportional to the rate at which field lines are cut".
I would like to be able to independently control the primary voltage and the turns ratio. Even better would be able to control the load on the secondary and the a.c. frequency but these are low-priority requests!
Any help with this would be extremely welcome as I find that my students (high school) have great difficulty envisaging electromagnetic induction in a transformer due to the lack of physical movement.