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Author Topic: Radiant Electriciy Generated with Spark Gaps and Induction Coils - Theory  (Read 52740 times)

antimony

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I did not want to post a new thread about what i "discovered" just now.
Its new to me at least.

I am starting out playing with my Tesla coil/Moroz spark gap generator when i tried to ground my spark gap and The flourecent bulb lit up to like 80% and The amp wen down from 1,6 down to 0,8 A.

What happened? :)

TinselKoala

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You went from having an extremely inefficient circuit to one that is just very inefficient.    ;)

antimony

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You went from having an extremely inefficient circuit to one that is just very inefficient.    ;)

Haha, yeah. Thats right. :)

I am just starting out playing with these sort of "systems" or technology, and i was surprised when the bulb lit up like that.
The flyback starts to ring, and the SG doesn´t spark anymore, at all.

Anyway, it doesn´t light up an incandecent bulb at all, so i guess it needs more current, or what? 


AlienGrey

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It's a simple fact the base of the Tesla coil is CURRENT (Amps) and the Topend is High Voltage, BEMF is produced when the magnetic field collapses in the drive coil, the lower the circuit resistance in the on off switch the higher the BEMF. If you experimented you would already know that.

AG

antimony

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It's a simple fact the base of the Tesla coil is CURRENT (Amps) and the Topend is High Voltage, BEMF is produced when the magnetic field collapses in the drive coil, the lower the circuit resistance in the on off switch the higher the BEMF. If you experimented you would already know that.

AG

Ok, im not 100% sure that i understand what you mean, but it clarified alot thou. I am going to check it out.

Yesterday i tried to put a ground on the base pin of my TIP3055 flyback driver, and the amp draw decreased by 0,2A, to 0,6A, while the small 11 watt bulb lit up a bit more, (~5%).

Did this lower the circuit resistance in the driver, or do i understand it all wrong?

dieter

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From my POV, whenever there is a BEMF, there is a strong pull during which "the ground" becomes the positive pole. As its potential is the same as before, the BEMFs negative pole must be more negative than the ground. Therefor current may flow out of the ground. Same thing with lightnings that start at the ground.


A BEMF also pulls in other kinds of forces, radiant forces for instance.


Experimenting with a 3kV Sparkgap, shocking a graphite core, I observed strange reduction of power consumption: a coil around the core was pulsed at maybe 15kHz with short duty, the BEMF rectified and fed back into the battery, that run the whole 555+npn pulser unit. Even tho the 555 alone draws 10 mA at least, this circuit run for hours and barely drained the battery.
I had a strong feeling that the sparkplug and its cable that run diamerticly trough the coil, somehow greatly beefed up the BEMF.


Other things were: sparkgap increased in frequency and loudness, (a 3kV module running from seperate 3*1.5V batteries) despite the batteries voltage that you would expect to fall.

nix85

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Re: Radiant Electriciy Generated with Spark Gaps and Induction Coils - Theory
« Reply #22 on: September 11, 2021, 03:54:44 PM »
It's a simple fact the base of the Tesla coil is CURRENT (Amps) and the Topend is High Voltage

I seen this claim floating around and it's just wrong. Current is same in whole secondary coil, from bottom to top. Unless we are talking Don Smith center tapped and probably bucking secondary volt-amp separation which is another story.

nix85

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Re: Radiant Electriciy Generated with Spark Gaps and Induction Coils - Theory
« Reply #23 on: September 20, 2021, 03:30:00 PM »
Gotta correct myself, it seems this is commonly accepted for all antennas. See image below. Why i thought different is if you look at this representation of standing wave on a half wave dipole https://youtu.be/OuVQqFhualI?t=89 As you can clearly see there is one uniform current along the dipole. Question is if this IV nonlinearity happens also when antenna is not grounded.

nix85

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nix85

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Re: Radiant Electriciy Generated with Spark Gaps and Induction Coils - Theory
« Reply #25 on: September 20, 2021, 07:16:14 PM »
Another good video about this

https://www.youtube.com/watch?v=7Sgtq-ncZAE

I knew this but i didn't apply it to Tesla coil secondary. I already talked on this forum how impedance of an antenna is repeated every half wavelength down from the antenna, it does not matter what the characteristic impedance of the transmission line is (have to take into account velocity factor of the feedline).

Z = sqrt( L / C ) transmission line characteristic impedance

Along the open ended transmission line voltage and current waves reflect back and produce voltage and current nodes and antinodes 90° offset. Overall current being zero.

When we bend the end of the TL outward like an open capacitor we have an antenna and now energy can radiate.

We don't want standing waves along the transmission line which happens due to impedance mismatching of the antenna and the TL, only in the antenna itself. But there is no perfect matching so we have standing wave ratio etc.

Great demonstration of impedance matching vs standing/traveling waves.

https://youtu.be/DovunOxlY1k?t=795

onepower

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Re: Radiant Electriciy Generated with Spark Gaps and Induction Coils - Theory
« Reply #26 on: September 21, 2021, 04:33:56 AM »
Nix85

You are incorrect about the current being uniform in the secondary of a tesla coil with one open terminal.

First, the top or open terminal of the coil is the point of highest potential because the other end is usually attached to ground. Since it is at the highest potential it alternates between max/min charge density. Ergo the current cannot be the same at the top because the charge density is not the same due to the Coulomb forces present.

Thus as the potential changes so does the charge density and so must the motion of charges or current.

Your confusing a low voltage closed system with a high voltage open one which follows different rules.

Regards
AC




nix85

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Re: Radiant Electriciy Generated with Spark Gaps and Induction Coils - Theory
« Reply #27 on: September 21, 2021, 10:27:18 AM »
Seems you are incapable of understanding English. My post above literally says "Gotta correct myself" followed by a diagram showing IV distribution in the secondary and highlighted "current in the base is high and diminishes along the height of the coil". Which i further elaborated in next post about standing waves, IV nodes and antinodes in TLs and antennas and waves in any medium. I am not confusing anything, you are. This IV distribution applies to low voltages as well. Video of Jeri Ellsworth i linked clearly shows voltage and current distribution in a loop antenna with low voltage signal. Read, onepower, read.

Speaking of Coulomb forces you should've mentioned that Coulomb forces, that is, repulsion between electrons is the reason it takes higher voltage to pack more electrons on the plate of a capacitor, obviously, higher the electron density higher the repulsion to further electron inflow to the plate.

But electrons don't always repel, in superconductors they form Cooper pairs and their masses are less than masses of two electrons making them. Electrons also join in spark gap discharges in phenomena termed Electrum Validum aka 'strong electron' etc.

nix85

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Re: Radiant Electriciy Generated with Spark Gaps and Induction Coils - Theory
« Reply #28 on: September 21, 2021, 01:20:30 PM »
This is the best animation of halfwave dipole radiation, the memory effect aka kink etc.

https://www.youtube.com/watch?v=ZaXm6wau-jc

nix85

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Re: Radiant Electriciy Generated with Spark Gaps and Induction Coils - Theory
« Reply #29 on: September 21, 2021, 02:59:39 PM »
This video is bar far the best

https://www.youtube.com/watch?v=7Sgtq-ncZAE

I might also add a little about Helical antennas which i studied in depth years ago. Basically, if circumference of a coil is equal to a wavelength it will radiate circularly polarized waves in axial mode, that is, straight forward, they are used in space communication (because they are not angle-dependent and don't need perfect alignment), and if circumference is not equal to wavelength it will radiate sideways like a monopole. Circularly polarized waves can also be produced by two orthogonal halfwave dipoles 90° outta phase.
« Last Edit: September 21, 2021, 07:29:14 PM by nix85 »