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Re: Weird ideas


From: 	Jim Lux[SMTP:jimlux-at-earthlink-dot-net]
Sent: 	Sunday, November 30, 1997 3:29 PM
To: 	Tesla List
Subject: 	Re: Weird ideas


> 1) Earlier this month, we had discussion on using water as a dielectric.
> >From Jim Lux's post, we learned that water is a "slow" conductor. Will
it be
> practical to use water as choke by filling water in poly tube? If not,
why not?
Water has too high a resistance to be a useful choke. You'll lose all your
power in I2R losses. If you add a salt to it to make it a better conductor,
it doesn't have the strong time dependency anymore.  Nice thought,
though...

> 2) As the capacitance increases, high frequency current will pass through
a
> dielectric more easily. So, by putting poly between the primary and the
> secondary, instead of insulating the two, will it actually create more
problems?

Air, is of course, an insulator, as is poly. Poly does have a higher
dielectric constant, so it will increase the capacitive coupling between
primary and secondary, which may or may not be desirable.

> 
> 
> 3) I want to do some ball lightning experiment with microwave (I know
about
> the candle trick, it works!). Similar to what the Corums did, who excited
> two resonators will one primary, I am going to put two resonators in a
> microwave and excite it with one magnetron. Is microwave tranformer
shunted?
> Some say yes, but other say no. Who should I trust?

The trick will be in coupling the energy into the resonator. Why not build
a resonator with a port to match the microwave magnetron output flange? Get
the ARRL microwave expermenter's handbook(s) for basic info on building a
cavity, coupling, etc. Microwaves run in the ISM band at 2450 MHz. Be
careful about near field power density near the end of the waveguide or
cavity. The near field distribution looks nothing like the far field for an
antenna or stubbed waveguide, and can have significant lobes behind or next
to the antenna.

 Why would it make any difference if the transformer is shunted? In
general, modern microwave ovens are designed so that any mismatch won't
cause the magnetron to overheat. As long as you use the magnetron and
transformer from the same oven, you should be pretty foolproof.

By the way, there are a couple of companies making plasma etchers using
converted microwave ovens, coupling the power into a reaction chamber at
low pressures and creating a suitable plasma.

> 
> 
>   BTW, why bother with tubes? Frankly, I found that they are so
incredibly
> inefficient, think about this for a moment: First, you have to put enough
> energy to "boil" enough electrons. Then, you are applying electric field
> (energy) to constantly accelerate the electrons, not only did the
electrons
> did not slow down as they approach the anode, they travel at full speed.
At
> last, you stop the electrons and most of its energy become heat. Heat is
> generated in both the "boiling" and "stopping" process, it sounds to me
like
> a electron welder.

You can build a linear amplifier with tubes, reducing the harmonic content,
thereby possibly improving the efficiency of the Tesla Coil (depending on
what you mean by efficiency, of course). You are also less likely to
radiate EMI and bring the federales down on your head, although I don't
personally think this is a particuarly good reason in and of itself.