Re: Magnifiers

Replying to Rod on magnifiers...

> Question - what characteristics (w.r.t. the secondary) does the tertiary 
> coil need to have? ie, same number of turns, same frequency etc?

To drive a resonator at it's base, the base must seem as though it is
connected directly to ground and the ground made to move under it. The 
drive system then has to be a voltage source (resistance only with R 
ideally approaching zero ohms). Two ways of getting it : either a 
transformer (close-coupled pri-sec driver) with the primary driven by 
a very low impedance source, OR, in a loose coupled system, the 
secondary must appear series-resonant (present a resistance only) to 
the base of the resonator. I should note that a capacitor that has a 
rather low impedance at the resonant frequency is still only an 
approximation to a voltage source.
    I'm currently doing some theoretical work which should make the
design of a loose-coupled system a breeze. The tight-coupled one is
always going to work (fine-tuning of parameters notwithstanding) if
its frequency matches that of the resonator.
    One starts out with the natural frequency of the resonator, then
tailors the drive system to suit.