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Modeling a magnifier
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From: John H. Couture [SMTP:couturejh-at-worldnet.att-dot-net]
Sent: Thursday, March 12, 1998 12:42 AM
To: Tesla List
Subject: Re: Modeling a magnifier
Antonio -
I do not think the ground side of C3 should be hard wired to L2 as this
does not truly represent the TC secondary circuit. Your test circuit should
include an actual toroid (C3) in space with the earth (or metal plate) as a
ground. I do not believe there will be any oscillations because the
radiation resistance (Rr) will be greater than
sqrt(4L/C) After the gap has quenched (one shot) the toroid will
remain charged and will discharge as an aperoidic wave. However, the
question is "To what voltage should the toroid be charged in the test?" I
have not been able to find anything on this in the literature.
John Couture
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At 03:30 PM 3/9/98 -0600, you wrote:
>
>----------
>From: Antonio C. M. de Queiroz [SMTP:acmq-at-compuland-dot-com.br]
>Sent: Sunday, March 08, 1998 12:30 AM
>To: Tesla List
>Subject: Re: Modeling a magnifier
>
>John H. Couture wrote:
>
>> Tesla also said that the secondary was acting in the transformation mode.
>> This means it was not in resonance and the pri/sec voltage was the same as
>> the turns ratio of the windings. JC
>
>Correct, but this happens only while the gap is conducting. After the opening
>of the gap, the secondary is just a normal coil.
>
>> Could you explain the above in more detail. I'm confused about the energy
>> oscillating after the gap is quenched. JC
>
>Consider the circuit formed by the secondary coil, the third coil, and their
>self-capacitances. Ignore resistive losses:
>
>+-----+--L3-+
>| | |
>C2 L2 C3
>| | |
>+-----+-----+
>
>C2 includes the self-capacitance of the second coil L2, of the
interconnections,
>and the input capacitance of L3. C3 includes the self-capacitance of the
third coil
>L3 and the top capacitance.
>This circuit has two oscillatory modes, and if L2*C2=(L2+L3)*C3 it oscillates
>exactly as a two-coil Tesla coil, with the same beating waveforms, that
periodically
>concentrate all the energy in C2 or in C3. (This can be demonstrated by
using the
>equivalence between a transformer to a T circuit of inductors.)
>Actually, you can build a Tesla coil variation exactly in this way.
>This is a model for the magnifier circuit after the spark gap is quenched.
While
>there is energy in the system, the double oscillation occurs.
>
>Today I made some experiments at low power using the secondary of a Tesla coil
>that I am building for L3-C3, another smaller coil for L2 and a variable
capacitor
>for C2. I charged the system by switching a high-impedance current source
across
>L2. I could observe clearly the beating waveforms and the energy
oscillation when
>C2 was set according to the equation above, exactly as in simulations using
this model.
>I will prepare a full report about the experiment.
>
>Antonio Carlos M. de Queiroz
>http://www.coe.ufrj.br/~acmq
>
>
>
>