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Re: 50%

Hi everyone,
                I've been following a number of exceedingly 
interesting posts and threads on a number of topics and decided to 
post a general one to comment on each.

    First the 50% question. I second Bert's post on this, and 
furthermore, I suspect from what I now know about gap behaviour most 
of us are doing better when using the least lossy components we can 
get in the primary (secondary Q's are all pretty high). Abramyan's 
paper includes a graph showing efficiency vs Q for both coils and 
shows the efficiency climbing rapidly for high Q's in both coils. In
my opinion, attempts to get more bang for buck really are pushing the 
envelope. The key to this has to be the gap system if good quality 
components and grounds are used since the primary and secondary 
discharges are the defining losses, all else being good. k does not
affect efficiency in itself. Perfectly lossless coils coupled at
say, k = 0.000001 will _still_ be overcoupled. The point where k=kc is
defined by circuit losses. k merely defines the number of cycles it 
takes to effect the transfer. It should be remembered that efficiency
approaches 50% _at_ critical coupling (primary losses = secondary 
losses) when sparks are issued from the secondary.

     I should have added resistive losses in my answer to the 2-
capacitor problem. I was assuming lossless components but still 
coupled to "free space". If that coupling does not exist either, then 
the circuit will ring continuously. The problem is usually posed by 
stating that no resistance is present in the circuit. The trick is to 
identify that you cannot have a current flow without an inductive 
component being present and that in reality you then have a 
radiating circuit. If that had been the primary of a coil, its energy
would long ago have been transferred to the secondary at some k.
Some time ago, Richard noted that dynamic primary Q's are terrible.
I think it's important to recognize why. With the secondary sucking 
energy out of the primary, that statement is certainly true but the 
energy has usefully gone to the secondary by and large, not 
disappeared as heat or whatever.

          I noted with interest Richard's post on the charging by 
induction of the electroscope but then he mentioned charge leaking 
off the electroscope metal. Perhaps there is a minor inconsistency 
there? You can sit on one of the popular deck chairs (made of poly-
propylene incidentally - what an obscene use of a wonderful 
electrical material :( , rub the arm of the chair vigorously, and
feel the strong electric field present. The charge is got rid of by 
applying a conductor to the arm of the chair and letting the 
collected charge bleed away (e.g. breathe moisture on the chair and
wipe it with a hand while grounding yourself).
 
      On Alan's post on objective reality, this highlights a problem 
in quantum physics known as the "Copenhagen interpretation" of what
is happening. I think most scientists view quantum physics as a very 
handy recipe for devising new devices. I think few would venture to 
suggest that it is an accurate description of what actually happens
although experiments to resolve various paradoxes are pushing that 
envelope. Schrodinger arrived at the same conclusions as the 
Copenhagen school for atomic orbital behaviour from a classical 
viewpoint. The central paradox to my mind is: are things really 
happening that make processes fuzzy and unknowable or is it simply 
that we cannot in principle observe to the required resolution? For 
example, there is the famous "action-at-a-distance faster than c"
problem. To my mind, it's possible that people forget that "particle"
properties are correlated at the time the "particles" part company.
Measuring the properties of one means we can know the properties of 
the other. Should there be any mystery that when we also measure the 
second "particle" we find that it indeed has the properties that
measuring the first would suggest?

     Apologies to Chip for this off-topic ramble. I just wanted to
have a _single_ say on each of these things. BTW, congrats on 
successful firing of your rotary Chip. I can't wait to get mine into 
action as well. A word of caution might be in order though. Letting
it wind down should be done with a static gap planted firmly across 
it in my opinion or you could have a cap boom and bust due to un-
controlled choke/cap resonance.

     Down off the soapbox. Thanks for the many interesting ideas. I
must say Richard has rekindled my interest in electrostatics with a 
vengeance.

Cheers all,
Malcolm