[Prev][Next][Index][Thread]

Re: That secondary behaviour, E-Tesla5, and Corum's thing...

Terry & the rest-

More wonders of the computer age!  I printed out your Web image & have it
in front of me & it looks oh-so-familiar.  Except...the image I got on my
scope just this a.m. doesn't have the fuzz--hah!, hah!, hah!

What I did:  My ancient Wavetek 115 will emit a single sine cycle, at the
>end< of its gate input from the HP 8005.  I made it do that, then synced
the Tek 7904 from the beginning of the gate signal.  Thus, by choosing a
long enough sweep time, I could get the 1 cycle event-time fully to
appear on the screen.

Next I adjusted the Tek's 7B92A dual time-base plug-in to display that
whole 1-cycle time & a bit more all across the screen.  I displayed a)
the input 1-cycle to the bottom of the secondary and b) the signal at the
top via the 10:1 probe.  I left the probe galvanically connected to avoid
phase shift due to unknown series capacitance were I to just lay it near
(your point!).

Now here's the fun part:  My 7904 incorporates a 7D11 digital delay
plug-in.  It can make a little pulse & an intensity change appear on the
screen, digitally positioned anywhere along the display.  So, I set that
up & with it made the following measurements at resonance:

A.  Commencement of the 1 input cycle, 0 us, normalized.
B.  1st input peak, 2.7 us.
C.  Input z.c. (zero crossing), 5.6 us.
D.  2nd input peak, 8.3 us.
E.  Input end, 11.0 us.

F.  1st output z.c. (each z.c., eyeballed by choosing the place on the
wave equidistant between 0 or a preceding peak and the following peak),
3.2 us.
G.  1st output peak, 5.3 us.
H.  2nd output z.c., 7.8 us.
I.  2nd output peak, 10.5 us.
J.  3rd output z.c., 12.9 us (the coil is, of course, continuing to
ring).
K.  3rd output peak, 15.5 us.
L.  4th output z.c., 18.0 us.

>From the above:

1.  Successive output vs. input time delays, z.c to z.c & peak to peak: 
F-A=3.2, G-B=2.6, H-C=2.2, I-D=2.2, J-E=1.9.

2.  Free-ringing 1/4-cycle times, K-J=2.6 & L-K=2.5...& on & on.

3.  Input 1/4-cycle times, B-A=2.7, C-B=2.9, D-C=2.7, E-D=2.7

So what's it all mean?  It's straining at gnats, is what I think.  Sure,
there's an itty-bitty extra delay right at the beginning, & then the
output wave seems to speed up a tad just at the end of the input cycle
(anticipating the end, do you suppose?--a new phenomenon previously
unknown to science!).  Of course, I use not-necessarily-finely-calibrated
equipment but still, one can compare measurement to measurement pretty
accurately.  I think I find nothing of interest here:  The output wave is
going to settle down to being 90 degrees behind the input pretty damn
soon & after that, that's always the same.  I don't see anything that's
"slow".

Why am I still doing this??  I'm supposed to be retired!  Someone save
me!

Ken Herrick

On Fri, 14 Apr 2000 22:30:35 -0600 Tesla List <tesla-at-pupman-dot-com> wrote:
> Original Poster: Terry Fritz <twftesla-at-uswest-dot-net>

>snipped<

> I used a Tek TDS210 digital scope to capture 2500 points and read 
> them to
> disk and then to Excel.  I captured the graphs and converted them to 
> a JPG at:
> 
> http://users.better-dot-org/tfritz/site/misc/Ken01.jpg
> 
>snipped<
> 
> Be very careful of phase information with bare probe ends.  I 
> recently had
> a bad experience with that ;-))  I no longer trust the "little wire 
> on the
> end of a scope probe" for anything!  The tiny capacitance that is 
> coupling
> to the coil's fields to the probe (~0.03pF) is messed with heavily 
> by the
> probe's own impedance.
> 
> >
> >And once again, someone tell me what it is that's >"slow"<!
> 
> It comes from a paper by the Corums where they talk about their 
> "slow-wave
> helical resonator theory".  Basically, they claim that the Tesla 
> coil
> secondary is acting like a transmission line with a velocity factor 
> of
> ~0.1% (yes, they do claim 1/1000 the speed of light!).  So the wave 
> is only
> traveling 1862.8 miles per second.  Thus the wave is "slow".
> 
> See their paper (about 10 paragraphs in but mostly the whole first 
> part) at:
> 
> http://www.ttr-dot-com/corum/index.htm
>


________________________________________________________________
YOU'RE PAYING TOO MUCH FOR THE INTERNET!
Juno now offers FREE Internet Access!
Try it today - there's no risk!  For your FREE software, visit:
http://dl.www.juno-dot-com/get/tagj.