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T-line experiment worked!!
Hi All,
I did a transmission line vs lumped model test today that favored the
transmission line theory!!
The configuration is a bit far from a typical Tesla coil configuration but
I was surprised it worked!!
Basically, I drove my bare secondary from the base with a 33K resistor and
loaded the top with another 33K resistor (yes, I do read Bob's posts ;-)).
I think the characteristic impedance of my coil is about 31k ohms so I was
trying to set up a true transmission line with the right input and output
loading. The scope probes are 10M ohm at 16.6pF which does add a lot of
loading but the models account for that. I then checked the input and
output voltage from 100kHz to 2MHz in 100kHz increments. The diagram of
the whole thing is here.
http://users.better-dot-org/tfritz/site/misc/Terry01.gif
The MicroSim predicted outputs are very different between the two models.
"I" was hoping the lumped model would obviously win. ;-)
http://users.better-dot-org/tfritz/site/misc/Terry02.gif
Ha ha ha... As the real test data shows, the T-line model won easily!!
http://users.better-dot-org/tfritz/site/misc/Terry03.gif
Of course, the loading and fields around the coil in this none base
grounded configuration probably really do look much more like T-line than a
real coil. However, this does confirm a few odd tests like this that came
up with T-line results.
If one were to match the coil's characteristic impedance to the arc
impedance and the drive the coil with that impedance from the base, you may
have a real transmission line TC that would conform to this test's setup.
I don't know if a "real" Tesla coil could ever be made to work like this
since that base impedance is drastically different than what we are used
to, but who knows...
Cheers,
Terry