DaasYochid; on the larger picture, yes, I agree with you because-if you read the shmiras shabbos carefully-initiating an electic current is a “maase nolad” – akin to striking a match. although I am not sure whether that makes it a melocho d’oraisa on yom tov. He allows to use an electric stove but not to alter the current. However, this can be only be right if there is more than one coil-as cherrybim said- because if there is only one coil and you change the temperature by increasing the wattage ,why should it be “ossur”?
The question of electric currents was settled about a hundred years ago and ,regardless whether the science was correctly identified, “puk mo amo diber”. My only contribution was to say that ,on yom tov, the matter of electric currents is uniform-even if you believe it is boneh like the chazon ish. Of course, “mavir” and “mevashel ” are obviously allowed on yom tov. I quoted the tosefos to say that boneh,too, could be allowed on yom tov because of “mitoch”.
There may be questions on yom tov like, for example, a dimmer. Why should it be ossur to increase the strength of the light on yom tov? The electric current is already present, you are only increasing the wattage? I never heard a good answer on this. Maybe you can enlighten me. Decreasing the light is more complicated as it involves “kibui” and this is a discussion for another day.