Re: Pri./Sec. Tuning

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Christoph Bohr" <cb@xxxxxxxxxxxxxxx>

Hello Mike.

>    My confusion is sometimes I see people say tune your primary lower or
> higher. Shouldn't they ring at the same frequency?

They basicaly should be tuned to the same frequency.
But in most cases you choose the primary inductance a bit higher
compared to the values you derive from measurements with a scope.
This is done in order to compensate for the additional capacitive loading
of the secondary coil, induced by the capacinance of the streamers.
So the optimal tuning point for full power operation will be a bit more
to the outer edge of your primary, lets say an inch or two on a small coil,
ymmv..

>    Also as a tuning method, could you lightly couple a scope probe to the
> circuit and drive the primary with a signal generator, then watch for
> double peaks, then adjust the primary inductance (or capacitance) until you
> have a single peak.
a very basic approach ( but not without drawbacks ) is to drive your
secondary coil with a signal generator and look for the first peak, then tune
your primary to give a peak at the same frequency. Might not be "bleeding edge"
technology, but will give you a point to start from.
You may want to used the tesla coil tuner suggested by terry fritz
for this purpose. Easy and cheap to build and works great.

>   "clear plastic"? How do I find out what type of plastic this is?
> It has a 1/4" wall thickness.
I'm not an eypert on that, but clear stuff might not be the worst, but
other can cetrainly tell you more about this point.

best regards

Christop Bohr