What do we know about it?
I found some info in a book called practical trasformers about parametric transformers...
basically i understood the meaning of the word parametric excitation ... it mean excite by changing parameters.
On the parametric transformer no energy transfer occur because of flux linkage... the magic happens when theres absolutely no coupling.. although the magnetic field on the primary transformer mess around with the inductance of the coil on the other transformer core. So no reaction can exist... and the voltage output is a perfect sinusoid at the resonant frequency, and plus in quadrature...90° dephased with primary voltage as the magnetization depends on the current and thereto the modulation of the secondary inductance happens 90° after the primary...
the system resonates if driven at twice the resonant frequency. .
pretty nice stuff
the capacitance could be made to vary too...
