Quote from: Farmhand on January 14, 2014, 05:34:56 AM
A funny shaped piece of wire. Depends what you use it for.  I don't get it, no current no power, no current no magnetic field = no magnet.

Voltage causes current, no voltage no current.

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No current, no loss.

Maybe this is not the correct thread for me to respond either.

I just scanned the Patent and there is no mention of "resonance or resonant frequency ect." in the patent, so we can forget those "terms" in their strictest sense when talking of the patent.

Those are terms I used to describe the tuning of the capacitance to the Inductance,  and is how I describe tuning a resonant system to a load. I would describe right or wrong that Power Factor correcting is tuning the system to resonance on load. Maybe it's wrong to say that but that is what I mean.

Actually I guess tuning a resonant system to a load to get the most power dissipated as possible is more like "Impedance matching".

I don't see anywhere in the patent itself where Tesla himself mentions resonance or resonant frequency ect., someone should have mentioned that. Better late than never I suppose.

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From experiment with resonant setups like the one in the picture previous page, I can say that when at resonance if I add certain loads the input drops, the tank voltage drops, and the activity drops, but with a simple tuning of the output parallel tank the activity, the tank voltage and the output power can be controlled right up to max and the more activity and output the more input power it takes from the battery. If the setup is finely tuned that is.

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How about placing a piece of flat steel in close proximity to the coil to simulate a load for testing ? Induction heater.

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New video about the magnetic field strength of my two pan cake coil. Nothing new, I just used my power supply as a variable current source (as MileHigh taught me). So far I only used this "current feature" of my laboratory power supply to limit the current when testing new circuits (so that I did not fry too many transistors).

http://youtu.be/tvDUAcC1hbk


@Farmhand, MileHigh and Turbo:

I really like the discussion of this Tesla patent and the related "resonance and capacitor issues" (series or parallel LC circuits; impedance) because I only have a very muddled understanding of it. I will take some time till I understand the many posts, but then I will be back with questions.


@Magluvin and all:

I think we all are aware of the "high Voltage between adjacent wire turn" issue when talking and thinking about bifilar coils. The crucial problem is to describe the actual consequences.

- The known consequence of the "higher Voltage between adjacent wire turns" in a bifilar coil is the higher self capacitance (and the resulting lower self resonance frequency of a bifilar coil compared to a similar monofilar coil). This is nothing new in principle and no other effects are described in accepted science.

- Now there is a lot of esoteric and hype (or magic as I cynically like to call it) about alleged effects. I would like that someone describes at least one of these "magical effects" in clear and measurable terms. What is this "additional feature" of a bifilar coil (in comparison to monofilar coils). (Please do not say it is the high Voltage between adjacent turns).

- I have the suspicion that many people talk and write about "additional features" but can not really say more about it than the tiring "high Voltage between adjacent wire turns". Yes, there is "high Voltage between adjacent wires", but what does it cause (besides higher self capacitance)?

- I want to measure "unique features" (magic) of bifilar coils (besides the tiring "high Voltage between adjacent turns" which results in a higher self capacitance), but I do not know what to measure and nobody could tell me so far? (Some say there is nothing special, which is o.k. But the ones who believe in something special in bifilar coils should describe the effect more clearly.)

Greetings, Conrad

Well, the way I measured the coils in the second post gave me a different result altogether than this time. I remeasured the two coils and got a much higher frequency this time for both because I used the 10 K resistor on the ground leg of the function generator this time. I'll take time as soon as possible to update that first post to add the second set of measurements and explain there.

Anyway this time using a sine wave signal at full amplitude on the signal generator I get a frequency showing maximum wave amplitude at about 2000 kHz for the bifilar coil and about 2300 kHz for the monofilar coil as is, both have an Inductance of about 400 uH. If I put 115 pF in series with the positive lead of the Function generator on the monofilar coil it changes to about the same as the bifilar coil at around 2000 kHz. A difference of about 300 kHz.

This is a bit odd because going by the calculator online here - http://www3.telus.net/chemelec/Calculators/LC-Calculator.htm it would suggest a difference of only a few of pF between 12 pF and 16 pF along with the 400 uH to get those frequencies.

If I put the 115 pF in series with the bifilar coil it seems to increase the frequency required for maximum amplitude a bit if anything, maybe by as much as 100 kHz.

My Function Generator is very dodgy, it drifts a bit and is not so accurate, I need to get a digital one or something that will hold frequency with fine resolution.

The test setup I used tonight was the same as in the second post of this thread except that the 10 K Ohm resistor this time was in series with the Signal generator ground lead.

Cheers

AHAH, I read back and i will try with the 1 pF decoupling capacitor. And I can try an exciter coil as well. Will take some more time. The 115 pF of the scope is significant for these coils..

Quote from: Farmhand on January 14, 2014, 08:33:41 AM
Well, the way I measured the coils in the second post gave me a different result altogether than this time. I remeasured the two coils and got a much higher frequency this time for both because I used the 10 K resistor on the ground leg of the function generator this time. I'll take time as soon as possible to update that first post to add the second set of measurements and explain there.

Anyway this time using a sine wave signal at full amplitude on the signal generator I get a frequency showing maximum wave amplitude at about 2000 kHz for the bifilar coil and about 2300 kHz for the monofilar coil as is, both have an Inductance of about 400 uH. If I put 115 pF in series with the positive lead of the Function generator on the monofilar coil it changes to about the same as the bifilar coil at around 2000 kHz. A difference of about 300 kHz.

@Farmhand:

Just to make sure we use the same measurement method I attach two circuit diagrams depicting the "classical method for self resonance frequency measurement" and the "self resonance frequency mesurement with an exciter coil".

I agree that for 2.3 and 2 MHz a 1 pF decoupling capacitor to hide the ~100 pF of the probe is essential. I had great trouble to do consistent measurements between 1 MHz and 9 MHz without the 1 pF decoupling cap.

Greetings, Conrad