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Re: Basic Questions that I Know if I Would Think About It...
In a message dated 3/18/00 3:13:47 PM Pacific Standard Time, tesla-at-pupman-dot-com
writes:
<<
Well, the new pictures of the Veretus coil are being developed. We have
replaced our old coil with a new 8" (9.5" OD)) secondary with 34" of
21-gauge winding. The primary is 16 turns. We are using MMC caps right
now, which have a capacitance of about .01µf. However, we have plenty of
saltwater caps ready to be used just in case. What the problem is, though,
is that we cannot get it to break out of any toroid, even a small
corrugated one. (Well, we get very tiny sparks anywway.) When we take
the toroid off, we can acheive great several foot sparks from the piece of
magnet wire coming from the top of the secondary. As far as tuning goes,
we have already slid the primary tap all the way out to end of the 16
turns. From the way I figure, the secondary is probably too tall. Thus,
the secondary self-capacitance is too high and frequency is too low. (Or
something to that effect. :-) Please tell me if this sort of problem may
be fixed by changing the value of our primary capacitor, tuning inward on
the primary instead of out toward the edge like I thought, or shortening
the secondary. (Don't know if that one will work. :)) Thanks,
-- Ryan
>>
Ryan,
Don't shorten the secondary. You are already under a 4 : 1 ratio. It
definitely sounds like you are out of tune - needing more capacitance.
Calculate the resonant frequency of the secondary with the toroid. Now
calculate what primary capacitor you need with the primary tapped at about
80% to match that frequency. Use wintesla or my spreadsheet - or do it by
hand. I bet you need between 2.5 to 4.0 times as much capacitance as you are
using (.01 mfd).
Ed Sonderman