# chokes (and BIG Resistors) (power lost in RC)

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From:  Jim Fosse [SMTP:jim.fosse-at-bjt-dot-net]
Sent:  Saturday, May 30, 1998 12:32 AM
To:  Tesla List
Subject:  Re: chokes (and BIG Resistors) (power lost in RC)

>From:  Gary Lau  28-May-1998 0733 [SMTP:lau-at-hdecad.ENET.dec-dot-com]
>Sent:  Thursday, May 28, 1998 6:54 AM
>To:  tesla-at-pupman-dot-com
>Subject:  Re: chokes (and BIG Resistors) (power lost in RC)
>
[snip]
>The bypass caps are being charged to the high secondary voltage only 120
>times per second, twice per 60 Hz cycle.  I have yet to find a model that
>explains why the resistors get so hot.  Still unclear to me is, with
>resonant charging (between the NST and the primary cap), how much more
>than the 60 mA rating of the NST is being drawn.  2X?  4X?
>
Gary,
The current in a parallel resonant circuit is Q times the
input current. In this case, we are talking about the leakage
inductance of the neon transformer, it's secondary resistance, the
the C of the primary cap; ALL in a parallel resonance circuit. IIRC
Bert or Malcolm have measured Qs of 6 - 12 in this circuit. ergo: Iin
of 60ma => Iout = 60ma * (6 or 12) say 360ma to 720ma! So at 360ma
I^2*R (750ohms IIRC) => 97.2 watts! double that for a Q of 12. I'd
discourse does not include the effects of the spark gap shorting out
the resonant circuit which will, by inspection, lower the
dissipation.)

Hum, a question for Terry Fritz - have you considered scoping the
primary circuit's current waveforms for this effect with your fine
measurement setup?

aside: All, note that a 1 watt resistor will dissipate 1 watt but,
it's temperature will be 200 degrees Celsius above the ambient
temperature! That is how resistors are rated. I guarantee burnt
fingers, if you run a resistor at it's rated power level and touch it.

chills	;)

jim

p.s. at stp in air of course.

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