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What is the basic definition of a tesla coil

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thermite

Mon Feb 18 2008, 02:54AM

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Tesla is just the name of the inventor.

Is tesla coil a circuit ?

Is tesla coil a transformer ?

Is tesla coil an induction coil of the earliest type with a make and break contact in a solenoid ?

I am a newbie and look for a complete definition, and some variants of the basic embodiment.

I look for a clear paper or tut, but not a wild goose chase of needle in a hay stack in sites .

cheers

HV Enthusiast

Mon Feb 18 2008, 02:58AM

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Tesla Coil = Air core transformer

Arcstarter

Mon Feb 18 2008, 03:02AM

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high frequency air cored resonant transformer :)basically it works like a regular transformer except exact resonance is more essential.if you want a whole explanation of how it works let me know :)

thermite

Mon Feb 18 2008, 03:12AM

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arc-starter, thanks a lot for excellent start.

plzzzz give me the whole explanation.

thanks

Coronafix

Mon Feb 18 2008, 03:49AM

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Google is everyones friend.

Bjørn

Mon Feb 18 2008, 03:55AM

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This one is important too:

thermite

Mon Feb 18 2008, 06:25AM

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Quote from the first wiki link by goldsphere:

A Tesla Coil transformer operates in a significantly different fashion than a conventional (i.e., iron core) transformer. In a conventional transformer, the windings are very tightly coupled, and voltage gain is limited to the ratio of the numbers of turns in the windings. However, the voltage gain of a disruptive Tesla Coil can be significantly greater, since it is instead proportional to the square root of the ratio of secondary and primary inductances. The coil transfers energy from one oscillating resonant circuit (the primary) to the other (the secondary) over a number of RF cycles. As the primary energy transfers to the secondary, the secondary's output voltage increases until all of the available primary energy has been transferred to the secondary (less losses). Even with significant spark gap losses, a well designed Tesla coil can transfer over 85% of the energy initially stored in the primary capacitor to the secondary circuit.

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Who can show me any derivation of the voltage ratio of the loosely coupled coils as mentioned in the quote above ?

I know that for a single resonance circuit, the resonance can take the voltage of a cap to almost infinity and due to resistance you can use complex phasor analysis to find the upper limit.

No idea how to tackle loosely coupled resonant system.

Dr. Slack

Mon Feb 18 2008, 08:30AM

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For deriving the voltage gain, you can ignore the resonance aspects, that's just a mechanism that transfers as much of the energy from primary to secondary as losses allow, and do all the sums through energy.

Given that you know that E=1/2CV^2, and that at the voltage peak all the energy is stored in the capacitance and none in the inductance, then you can work out that the voltage gain (Vsec/Vpri) is just sqrt(Cpri/Csec) (neglecting losses).

BTW, try to avoid "almost infinity" in thinking about problems. For a single resonant circuit *being supplied with power* the voltage at resonance grows until it reaches equilibrium, that is the power loss equals the power supplied. The losses will come mainly from current flowing through resistances, though dielectric and radiation losses may add their tu'pen'th. Not so complex, and not a phasor in sight. Energy again, it's a damned handy concept!

Coronafix

Mon Feb 18 2008, 08:31AM

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Not sure if this is what you are looking for?!?

thermite

Mon Feb 18 2008, 07:17PM

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Now that I have shortened my sig and written it clearrly for safety tip, I would like to thank all those who replied yet.

However, I will work on trying to do the derivation. It is the starting point. The paper is a little too difficult and I would appreciate more references ... basic ones also to climb a smooth slope to this one.

Thanks again for your help and look forward to more.

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