The bifilar pancake coil at its resonant frequency

[MileHigh]

You calculated 0.98 uJ (microjoule) capacitive energy in a 49 pF capacitor when this cap has 400 V across it
as you defined in your example.

My calculation gives 3.92 uJ (microjoule). 

I think you mean pulsing a bifilar coil at a low enough frequency well away from its self-resonant
frequency, right? If yes, then this mode of operation is not comparable to the circumstances
defined in Tesla's patent.   

And there is no sense to compare 2.72 uJ energy in the coil to 0.98 uJ energy in the capacitor (this latter
energy is 3.92 uJ by my calculation), albeit this certainly fits to your apples to oranges comparison.

By the way, is there any sense for making such apple-orange comparisons?

This question arises because in your next text you introduce another example where the self-resonance
voltage across a coil is 40 Vpp and then you compare this 0.0098 uJ energy to another coil pulsed with
a low duty cycle 400 mA peak current that creates 2.72 uJ energy... 

It is okay that you can compare apples to oranges as you wish but such comparisons are good fun
for some people but surely not scientific at all.

I am not nit-picking with you, no offense intended at all, simply trying to find sense in some of your posts
and / or trying to correct mistakes other readers here may not recognise and from your posts they may remain
with the bad impression: a bifilar coil as per the Tesla patent is good for nothing.
And no, I will not answer your would-be next question: what is the advantage of using a bifilar coil...  lol

Gyula

Note that I said 400 volts peak-to-peak so I get the 0.98 microjoules from 200 volts.

The point of the exercise was just to try and get some kind of intrinsic feeling for what the bifilar coil's numbers and behaviour would be like in the real world.  Sure, I even stretched it to the point of breaking away from the Tesla patent and talked about pulsing the coil.  People are nearly obsessed with pulsing coils around here!  Like something like if you pulse the coil for say 50 milliseconds and you play with the timebase and gain and offset of your scope display you might see tiny bits of resonant ringing at the start and end of the pulse that you can trace back to the self-resonance of the coil.

And no, I will not answer your would-be next question: what is the advantage of using a bifilar coil...  lol

Sort of reminds me of this:   

http://www.reuters.com/article/us-alaska-bridge-idUSKCN0SI00120151024

[Magluvin]

ok,below is my bifilar coil.
It is made from heavy gauge rectangular ali enameled wire-so the winds sit nice and neat together.

I am just running an AC current through it,via my SG-so very low powered.

But here is the kicker,after a quick 10 minutes of testing.

The voltage generated across the sniffer coil,is in phase with the voltage across the bifilar coil,and not in phase with the current through the bifilar coil. The current through the bifilar coil is 90* out of phase with both the voltage across the bifilar and sniffer coils 

Tomorrow i will wind a single layer coil of the same amount of turns,and see if it is the same.


Brad

Nice. Can you show a closeup of the wire? I was just talking about square wire. Also could you measure the capacitance between the windings? Separated of course not in series connection. Just interested to see what you get.with that wire with more close proximity surface area.  Its gota be more than conrad had with the insulation and round wire. Not putting his effort down, just to see if you get better capacitance with what you got.

Mags

[Magluvin]

Silly question time.

Does the C need to be "pre charged" for it to cancel the L?

Does the applied voltage to the bifi pre charge the C before current flow?

This is what I was trying to explain in my understanding of the difference between a typical LC and a series bifi....

Like if we have a cap and coil in parallel and apply an ac input of the proper freq to ring, the induction is not ignored or even neutralized as tesla claims of the series bifi. The induction is there and functioning just as it should. If a pulse input is applied to the LC, the cap will charge fast and the inductor will impede the pulse. Then the cap will discharge into the inductor and ring till dead or till the next pulse. This is where Teslas claim is different. He is basically saying the capacitance 'in' the series bifi will take on charge ignoring the inductance, or as he says it is neutralized. So what does that mean for current entering the coil from the initial application of input???  Im thinking it means the coil will build a field either instantly or even much faster than a normal inductor of the same wire and size. Normally we are restricted to particular upper freq limits of inductors as they are low pass filters. But what if that same inductor were able to reach max current much faster or even instantly if the inductance is ignored or neutralized?? What affect would that have on a secondary vs a slow climb with an inductance that only lets the current rise in the pri over time?

So the 2 are not the same. The LC cap and separate coil are one thing and the bifi is another. The bifi coil takes on current, through the windings to charge the capacitance. And if the inductance is neutralized due to the coils structure capacitance change, then that capacitance should charge as fast as a cap, AND produce a mag field that builds as fast as the bifi cap will take the current from the input. So IM thinking the 2 are different and we will have to see.

Mags

[Magluvin]

Mags:
(no bitch)

BITCH !!

Yes. Tedious. And nice. 

Mags

[Magluvin]

Dang, lets all just get together and have a bifi coil show!    Nice


Mags