[Fwd: Re: [Fwd: Re: [Fwd: Re: hyfrecator]]]

    The following is from a private E-Mail message between
Kristen Ukkonen, Brent Turner, and myself.

The question is: Does a flyback transformer in a T.V. resonate
                 at 15 KHZ, the horizontal scan frequency?

Comments always welcome.
D. Gowin

  [ Part 2: "Included Message" ]

Date: Wed, 11 Dec 1996 17:48:53 +0200 (EET)
From: Kristian Ukkonen <kukkonen-at-cc.hut.fi>
To: Dan Gowin <gowin-at-epic-1.nwscc.sea06.navy.mil>
Subject: Re: [Fwd: Re: [Fwd: Re: hyfrecator]]

> operate at the horizotal frequency. And, the push pull circuit
> that we coilers use in our solid state Tesla coils is very similiar
> to the horizotal circuit in a T.V.. So, the question is. Is solid
> state Tesla coil "A Tesla coil" or are we simply driving a simple
> induction coil? Or another question, by definition a Tesla coil
> can only be an air resonate transformer?

It's a tesla-coil as long as it's resonant.. On the other hand,
flyback xformers in TVs etc. are not resonant and thus not 

> When I allow the field within an ignition coil to collapse the
> output (o-scope) definately rings as if it were resonate. Or,

It's rings because there is L and C in the circuit.. 

>> >       The flyback transformer in a TV is a Tesla coil. The flyback
>> > is designed to resonate at the horizontal scan frequency of 15 KHZ.
>> > D. Gowin
>> Not true. A flyback xformer is not resonant. It just dumps the
>> energy into the core and thus gets HV to secondary because
>> of inductance in secondary.. Simplified..
>> Kristian.
>Dan, I disagree with Kristian's statements. The photo in my book should
>clear up any confusion. When I adjust the timing parameters, there is
>a SPECIFIC frequency where the output signal really lights up! At this
>point, the scope shows peak voltage waveforms, classic exponential
>decay, and absolutely NO phase changes in the output waveform. If that
>ain't resonance, I don't know what is...
>- Brent

Surely, there can and will be resonant frequencies with the flyback
transformer but IN IT'S NORMAL USE it's not run resonant! 

Heck, I'll have to actually measure the resonant frequency of several of
the flybacks I have around here.. I'd bet that their resonant frequencies
vary a great bit! Depending on core material, number of turns,
size and shape of coil etc..

Just think about it - assuming they are resonance driven would imply that
ALL the flybacks would have to be carefully and accurately manufactured to
be resonant at the spesific freq..  Possible, but I don't think so..

Of course, I CAN be wrong but I strangely remember that some flybacks were
resonant near 50kHz or 150kHz.. I'll have to MEASURE it to be certain
though.. It's simple enough - if all the flybacks are resonant at
the same freq. than you are correct..

I'll mail you again after I measure some during weekend.. 

Anyway, iI do KNOW that flyback xformers are not resonant driven in

One more idea - if it were a resonator what would happen to it's res.freq.
when you connected it to the picture tube - I'd guess the tube would act
like a capasitor (toroids in TCs). One would need to assume that a
specific flyback would need to be optimized with certain CRTs as

Besides, I've seen a neat system running a flyback at 100Hz and getting
10cm (!!!) sparks out of the poor thing. Definitely not resonant, just
lots of energy dumped to the core FAST.. The energy magnetically stored in
the core is the source for the secondary voltage.. Like in induction coil,

Ideas and corrections welcome,


| Kristian Ukkonen       |  Do as thou wilt shall be the whole of the law |
| kukkonen-at-alpha.hut.fi  |_____  Chance favours the prepared mind  |-------
| http://www.hut.fi/~kukkonen |  Fear is the mind-killer  |---------
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