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Re: More maggie Q & A
Dr. Resonance wrote:
> Using the information in the archives, actually measure your coeff. of
> coupling before operation. Set it at 0.6 for for magnifier applications.
> There are certain values of coupling that provide optimum operational
> points, and 0.6 is one of them.
This, including the resonator coil (L3) too. Measure the coupling
coefficient k12 between L1 and L2, and make:
ktotal=k12*sqrt(L2/(L2+L3))=0.6.
This is the relation that causes the requirement for tight coupling
between L1 and L2. Note that there is no solution if L3>(16/9)L2,
what makes the resonator's inductance less than 1.78 times the
inductance of the driver L2 in this case.
Larger resonators can be obtained with smaller effective ks. The
next optimum ks are 0.38, 0.28, 0.21,..., (2n-1)/(2*n^2-2n+1),
where n is the number of semicycles required for complete energy
transfer.
The other relation that must be kept is L1C1=(L2+L3)C3, where C3
includes the top terminal capacitance and the self-capacitance
of the resonator. But this can be adjusted by tuning the primary.
If the required coupling can be obtained with the autotransformer
driver that you suggested, a magnifier that is close to one of
the optimum designs will be obtained.
With L1 and L2 wound concentrically, at small distance, there is
a relatively large capacitance in parallel with L2, and the triple
resonance design (the formulas that I posted some days ago) may
produce better results.
Antonio Carlos M. de Queiroz