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Re: Filtering on Neons

In a message dated 96-01-30 18:37:45 EST, tesla-at-grendel.objinc-dot-com writes:

>Well, I put two beads each on both lines out of the transformer secondary,
>and a couple more on the feed to the high voltage transformer. I think the
>performance of my coil was unaffected, by and large. However, I did find
that
>the addition of the ferrites shifted the tuning position of the coil - I had
>to
>use an extra two turns of primary.
>
>I have implemented a whole range of EMI measures, because I am running the
>thing
>in the middle of our lab at work. There is a radio which sits about 6 feet
>away
>from the coil, and the interference is minimal, all things considered. You
>know
>how sensitive a radio receiver is!
>
>Cheers
>Phil
>
>

Phil,

The electronics industry has used ferrite beads for a long time to reduce
radiated emissions from electronic equipment - usually to mask design
problems inside the box.  You see them frequently on older computers,
monitors and keyboards.  These are usually molded on the interconnect cables
right close to the device.

As I understand, you put these beads on the input and output leads of the
high voltage transformer powering your Tesla coil.  They should have had no
effect at all on the tuning of the coil.  The frequency of the tank circuit
comprised of the primary, capacitor and the spark gap should have been
unaffected.  Maybe there was some unwanted feedback or oscillations happening
between the tank circuit and the transformer - and the beads stopped this,
allowing a much better tune on the primary.  Did the performance of the coil
increase?

Ed Sonderman