Re: Parallel and Series LCR Circuit Qs

[ghub005-at-xtra.co.nz (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

> Original poster: "Richard Kircher" <richard.kircher-at-worldnet.att-dot-net> 

<snip>

>  Most confusing to me is impedance matching to the load/streamer. 
>  Some
> folks think that the most power transfer occurs when the source
> impedance is matched to the load impedance.  Don't try that idea with
> your car battery.  The most power transfer occurs when the source
> impedance is ZERO ohms and this applies to all lumped component
> circuits.  Of course, absolute zero is not achievable especially when
> the Cp/Cs ratio is high in the world of realizable coil parameters. 
> Given that the streamer impedance can't be changed or matched, it
> would seem the only thing left to do is to make the coil output
> resistance as low as possible (high efficiency) and match the reactive
> component.  

Richard

Surely a source impedance of zero ohms means that your power 
source also has a zero output voltage? (Ohm's law)

For maximum power transfer you will need to make the TC's output 
impedance equal to the complex conjugate of the spark impedance 
i.e. match the resistive componets and reverse the reactive 
component. This will give you a theoretical maximum efficiency of 
50% (as at least half of the power will always dissipated in the 
source impedance).

Of course, the spark impedance probably isn't linear - so all this 
may be moot. I would recommend that you just aim for the ballpark 
and concentrate on reducing losses in the SG and primary etc etc.

Safe coiling,

Gavin Hubbard


>  Terry's work indicates that the streamer impedance is capacitive (1pF
>  per
> foot)  Therefore it sounds like the coil should be inductive to tune
> it out.  Alternately, it would seem that the streamer de-tunes the
> coil and lowers the secondary resonate frequency.  So, I guess the
> primary should be tuned lower in frequency than the secondary to start
> with (?).  I wonder how much lower?  Maybe the answer is to just tune
> the coil by trial and error until the maximum streamer length is
> reached and forget about the grid dip meter.  Any ideas about this (or
> any ramblings) would be welcome.

<snip>