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Re: TC Critical Coupling

Hi John,

> Original Poster: "John H. Couture" <COUTUREJH-at-worldnet.att-dot-net> 
> 
> 
>   Malcolm, All -
> 
>   I agree that critical coupling MAY not produce an optimized coil.
> 
>   What is your definition of an optimized coil?
>  
>   My difinition of an optimized coil is the coil with the maximum percent
> efficiency for the input energy. I show a percent efficiency test in one of
> my books. Note that magnifiers may not work because they have additional
> parts that cause losses.

My definition of an *ideal* coil is one that loses all energy in 
output sparks, produces the longest sparks for the power input in 
repetitive operation, no energy loss in the primary or charging 
circuits and operates with unity power factor. My definition of an 
optimized coil is one that comes closest to the ideal.

>   How would you test to determine if the coil is optimaized? You can forget
> about the random extra long spark because that doesn't make engineering
> sense. The true input and output energies (volts, amps, dt's) of that random
> spark, of many sparks, cannot be determined. The one shot test also is
> useless, or is it?

I have learned an awful lot about TC operation without destroying 
anything using single shot tests. 

>   You misunderstood my explanation about raising the coil. If the critically
> coupled coil does not have to be raised because it is properly designed at
> the start the critically coupled coil MAY produce an optimized coil. Only
> building and properly testing a lot of coils can solve this problem.
> 
>   John Couture

A critically coupled coil is one that loses equal amounts of energy 
in its primary and secondary circuits. That is part of a formal 
definition of critically coupled tuned circuits. You will find it in 
any work (such as Terman) where critically coupled circuits are 
discussed. I've already stated my thoughts on why such a definition 
is irrelevant to Tesla Coils.

    BTW, I'm sorry - I forgot to answer a specific query in one of 
your posts. The value of k was about 0.15 in the small coil wh
transfer I measured at 85 - 90%. 

Malcolm