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Re: Elementary Lecture
to: Dave Hartwick
It's not magic -- it's physics. A Tesla coil produces "displacement
currents" in air because the air represents a dielectric while the terminal
represents a plate of a capacitor. The second plate is represented by
isotropic capacitance and plate to ground capacitance of nearby room walls,
etc. A displacement current has unique and different properties than normal
air to ground currents which produce the wandering spark phenomonea of Tesla
oscillators.
You might read some early Maxwell for good descriptions of displacement
currents.
Regards,
Dr.Resonance-at-next-wave-dot-net
-----Original Message-----
From: Tesla List <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: Thursday, February 25, 1999 7:35 PM
Subject: RE: Elementary Lecture
>Original Poster: "Dale, Martin" <martin.dale-at-ntu.ac.uk>
>
>
>
>> ----------
>> From: Tesla List[SMTP:tesla-at-pupman-dot-com]
>> Sent: Wednesday, February 24, 1999 11:08PM
>> To: tesla-at-pupman-dot-com
>> Subject: Re: Elementary Lecture
>>
>> Original Poster: Brandywine <brandywine-at-writeme-dot-com>
>>
>> Why sparks will leap between the toroid and a grounded object is quite
>> understandable; but the magic of a Tesla coil is that sparks
spontaneously
>> branch
>> out into thin air, connecting with seemingly nothing.
>> Consider 2 devices: A million volt Tesla Coil, and a million volt 60
Hz
>> transformer. The TC will emit a discharge into the air that connects to
>> nothing.
>> We'll help the million volt xfmr by grounding one of the secondary HV
>> terminals.
>> Do sparks spontaneously emanate from the other HV terminal into thin air?
>> No.
>> I certainly have not read all available Tesla coil theory, but I've
yet
>> to see
>> a thorough explanation of why a Tesla Coil does what no other device can
>> do--emit
>> sparks that terminate in the air.
>> Dave Hartwick
> >snip
>
>Hi Dave, et al
>
>I'm not sure of the best way to put this in elementary terms, but surely
the
>only way to understand why the H.F &H.V output from a TC has a greater
>propensity to produce a streaming discharge to air than that which comes of
>an equivalent potential 60Hz terminal, is to understand isotropic capacity.
>
>The isotropic capacity created by a Tesla coil terminal to the surrounding
>air, creates a much heavier load (lower impedance) at the coil's frequency
>of say 250 KHz, than at the mains frequency of 60Hz.
>
>If you replaced the air surrounding a 60 Hz terminal with a medium that
>better matched it source impedance, then I'm sure you would have the same
>effect.
>
>I'm not sure what the dielectric constant of water is (very high!), but
>surround the 60Hz terminal with that, and you may get the same effect!
>(though please dont try it!!)
>
>Explaining principles we may know well in our own understanding, to others
>in their understanding, is one of the most challenging things I can think
>of!
>
>A classic question I was once asked was "what exactly is a radio wave?"
>
>Knowing what it is, and saying what it is are 2 completely different
things!
>
> cheers, Martin Dale TCBON Nottingham UK
>
>ps, you will get a small amount of streamer output at 1MV 60Hz!
>
>