Re: mini coil primary coupling ?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Stephen Conner by way of Terry Fritz <teslalist-at-qwest-dot-net>" <steve-at-scopeboy-dot-com>

At 16:43 21/05/03 -0600, you wrote:
>Original poster: "Peter Lawrence by way of Terry Fritz 
><teslalist-at-qwest-dot-net>" <Peter.Lawrence-at-Sun.COM>

This confused me endlessly until I was lucky enough to have Paul Nicholson 
explain it to me.


>My precise questions are:
>1. should the primary and secondary be tuned (separately, in isolation) to
>    the same frequency,
>    and adjust the K (by varying coil proximity) to get a K of 0.180,
>    and then expect to observe at run-time the coils oscillating at the 5:6
>    ratio,

Yes.


>3. of the a, b, which is the primary and which is the secondary. if the
>    "first notch" is always at (b/2) then b has to be even, and we only
>    have 5:6, 7:8, 9:10,... modes available (not 6:7, 8:9,...). Am I
>    understanding this correctly?

The two resonant frequencies are properties exhibited by the coupled 
system. It's not valid to say that one coil oscillates at frequency 1 and 
the other oscillates at frequency 2. Both coils oscillate together at both 
frequencies simultaneously, or something %-$


>Since I don't have an O-scope, it would be nice to have theory predict what
>to build, and then have it come out working (or to put it another way,
>experimenting is nice, but after a while you want to understand why it
>works the way it does).

If you design your primary and secondary circuits to ring at the same 
frequency in isolation, it'll work when you put them together. You don't 
need a precise value of coupling. I don't think it really matters if you 
end up running in mode 50:61 instead of 5:6. It just means that the notch 
doesn't coincide with a zero of the oscillation so it's not a perfect notch.

Steve C.