Re: RF safety

["Jim Lux" <jimlux-at-jpl.nasa.gov> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

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> From: Tesla list <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: RF safety
> Date: Saturday, July 22, 2000 10:30 AM
> 
> Original poster: "Kennan C Herrick" <kcha1-at-juno-dot-com> 
> 
> > At 01:46 PM 7/21/00 -0700, Jim Lux wrote:
> 
> >snipped<
> 
> >A duty cycle of 10% or even 1% might not be a bad estimate for a
> > typical TC, when actually making sparks ( for a loaded Q of 10, at 
> >100 kHz, the RMS value of the first 100 cycles (1 mSec) is 0.22 times
> >the peak value of the first cycle, and an additional cycle only raises
> that >about .001)..
> 
>  >snipped<
> 
> I wonder if Jim means "...of the last cycle...", not the first cycle.

No.. If you take the peak value of the first cycle as 1... Then, take the
first 100 cycles and compute the RMS value, it comes out to .225... 
(y(t) = cos(f*2*pi*t)*exp(-kt), where k is set to make exp(-kt) = sqrt(.9)
with f*t = 1, that is, 90% of the RMS value at the first cycle(i.e. a Q of
10...)  For f = .1, k is about .005...)
> 
> Also, I can attest to the larger field when not "breaking out", that Jim
> mentions:  With no spark, my s.s. coil lights up all the flourescent
> lights, misc. neon tubes lying about, etc., in my workshop.  With a spark
> there's very little of that.  A subjective measurement, but indicative.

Well, just at first glance, I'd say that it's a radiated vs dissipated
field issue.  Gor the same coil (tuned the same), if you aren't making
sparks, the field is bigger, because there isn't any power being dissipated
in the spark.. it's all being dissipated in the secondary and primary
resistance, which has to be bigger (R, that is) than the effective R of the
spark.
> 
> Ken Herrick