The bifilar pancake coil at its resonant frequency

[MileHigh]

Not needed MH,, keep it nice please.
Then is the question more like,, Does the coil when it has no impedance produce a magnetic field?

I think that you could see that a coil that could instantly produce a magnetic field could then have an adjacent coil that is open while the field is created  and then closed to a load would slow that field collapse.

Then go scold Magluvin for suggesting my motives are nefarious.

Does the coil when it has no impedance produce a magnetic field?

That is another nonsensical question.

[TinselKoala]

Mags said,

Tesla says in the pat  that the bifi coil will accept an input and ignore the coils induction and will only be impeded by the resistance of the coil a a whole. Read that again and let it sink in.

Actually, what Tesla says in the patent is that _ANY_ and _EVERY_ coil acts this way if the right capacitance and frequency are used.

Quoting Tesla's patent 512340:

l have found that in every coil there exists a certain relation between its self-induction and capacity that permits a current of given frequency and potential to pass through it with no other opposition than that of ohmic resistance, or, in other words, as though it possessed no self-induction. This is due to the mutual relations existing between the special character of the current and the self-induction and capacity of the coil, the latter quantity being just capable of neutralizing the self-induction for that frequency. It is well known that the higher the frequency or potential difference of the current the smaller the capacity required to counteract the self induction; hence, in any coil, however small the capacity, it may be sufficient for the purpose stated if the proper conditions in other respects be secured. In the ordinary coils the difference of potential between adjacent turns or spires is ,very small, so that while they are in a sense condensers, they possess but very small capacity and the relations between the two quantities, self-induction and capacity, are not such as under any ordinary conditions satisfy the requirements herein contemplated, because the capacity relatively to the self-induction is very small.

"in any ordinary conditions" meant, in Tesla's day, at "low" frequencies, ie under 1 MHz, and with wires and insulations he had available.

We have been over this time and time again. The advantage of increased distributed capacitance in the TBF winding was that "the proper conditions" for attaining this counteraction of self induction could be attained at a lower frequency, that is, at a frequency he could reach with his apparatus, and ideally without the use of expensive, cumbersome and difficult to maintain condensers (capacitors). Today, and for a long time, capacitor technology has improved to the point where the required condensers to attain the "proper conditions" in ANY and EVERY coil are cheap, compact and require no maintenance. Compare if you will a modern strontium-titanate HV doorknob capacitor with a Leyden jar of the same capacitance and voltage handling capability.

Quoting Tesla's patent 512340:

The effects of self-induction, above referred to, are known to be neutralized by proportioning to a proper degree the capacity of the circuit with relation to the self-induction and frequency of the currents. This has been accomplished heretofore by the use of condensers constructed and applied as separate instruments.  My present invention has for its object to avoid the employment of condensers which are expensive, cumbersome and difficult to maintain in perfect condition, and to so construct the coils themselves as to accomplish the same ultimate object.

"Heretofore", that is, before the patented invention, that is... in "ordinary" monofilar coils.



Is it starting to sink in yet?   

[TinselKoala]

And... by the way... capacitors take time to build an electric field and charge up to a given voltage, and inductors take time to build a magnetic field and pass a given current. Nothing happens instantaneously.

The time required for the current flowing in the LR series circuit to reach its maximum steady state value is equivalent to about 5 time constants or 5τ. This time constant τ, is measured by τ = L/R, in seconds, were R is the value of the resistor in ohms and L is the value of the inductor in Henries.

http://www.electronics-tutorials.ws/inductor/lr-circuits.html

[TinselKoala]

1 watt hour of power generates 1 Tesla of magnetic force in a coil of 1 Henry of inductance. How come no one could answer this question?

None of these "F" in inductance people can define "Negative Current" either!

Positive power goes in one electrode of the coil and out the other. When the power's interrupted, negative current leaves the coil in the same direction as the positive current did.

The watt-hour is NOT A MEASURE OF POWER. And there is no difference between the current leaving the coil in the same direction when power is interrupted, and the current leaving the coil when the power is on, except that the current when power is on may be steady-state, and the current when power is interrupted is decreasing. Your "negative current" is a misnomer.

[TinselKoala]

I am in total agreement on the fact that the field collapse generates a current in the same direction of the input that built it. Could someone misinterpret a scope shot, seeing the voltage differential change at the time of input connect then disconnect as a current reversal? Maybe thats the bungle here?

Mags

Yes, and not only that but the scope probe adds substantial capacitance and can cause ringing, which complicates the picture considerably. The LED tests that I and TinMan have shown and proposed eliminate these problems and give unequivocal and easy (for most people) to interpret results.