Re: Secondary Voltage Measurement with CRO

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>

Hi,

I have noted a number of harmonics in the low MHz region.  I found that if
I shortened, lengthened, or otherwise played with the primary circuit loop,
that the frequency would change as well as the amplitude of the harmonics.
Getting BIG ferrits beads and placing them over the primary wires helps a
lot as I do for my small coil:

Look hard on the white primary wires...
http://hot-streamer-dot-com/TeslaCoils/MyCoils/SmallCoil/small_coil2.jpg

They are from Digi-Key who sells a wide varitey of sizes include the BIG
ones ;-)

Cheers,

	Terry


At 11:31 PM 12/30/2000 -0500, you wrote:
>Hi Ted,
>
>Very interesting that the 3.5 MHz signal is only present while the coil
>is running. Are you by chance using chokes in the primary supply? If so,
>does their inductance and the tank capacitance calculate out to this
frequency?
>
>How does the amplitude of this parasitic compare to the fundamental at
>95 KHz? Is the parasitic Fo sensitive to probe placement?
>
>Another thought, with the scope probe and foil it seems your trying to
>approximate Terry Fritz's plane wave antenna. If the probe is
>responsible for the resonance, you might try a swamping load resistor
>across the probe.
>
>I plan to build a plane wave antenna myself in the near future, time 
>permitting.
>
>Keep us informed on this.
>
>Tesla list wrote:
>> 
>> Original poster: "tesla by way of Terry Fritz <twftesla-at-uswest-dot-net>" 
><tesla-at-paradise-dot-net.nz>
>> 
>> Hi
>> CSC in NZ is 4.43MHz, the signal I was observing was from the tesla as it
>> was only present when the tesla was run. I think what I may be seeing is a
>> parasitic resonance enhanced by a rising freq response from the measurment
>> method.
>> Tnx for thoughts
>> Best
>> Ted L
>> Subject: Re: Secondary Voltage Measurement with CRO
>
>snip
>-- 
>Jon G. Tebbs
><jgtebbs-at-eos-dot-net>
>