Current passing through the primary coil creates a magnetic field.
The primary coil may be excited by any desired source of high frequency current.
A single primary coil can provide power to multiple secondary coils at the same time.
To progressively feed energy/power into the primary coil with each cycle, different circuits can be used.
The magnetic field of the primary coil collapses rapidly.
Changing the current in the primary coil changes the magnetic flux that is developed.
Referring to the two figures here, current passing through the primary coil creates a magnetic field.
A capacitor is placed across the points which absorbs the energy stored in the primary coil.
The resistance of the pot, as viewed from the primary coil, appears larger.
The primary coil drew its current from a small generator, which in turn could be activated by the 2-peak hypercom signal.