Re: LTR question

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

Original poster: "Luc by way of Terry Fritz <twftesla-at-qwest-dot-net>" <ludev-at-videotron.ca>

Hi Steve,

You're right this resonance do not apply to primary circuit, but
on the NST-cap couple. You could use a resonant cap size with the
NST but if you don't have a spark gap conduction at the right
moment, the voltage in your cap-NST could go really high and
could destroy both your caps and NST. It's a common practice to
used a LTR cap size to prevent this effect.

Cheers,

Luc Benard

Tesla list wrote:
> 
> Original poster: "Steve White by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<slwhite-at-zeus.ia-dot-net>
> 
> I have been reading a lot of posts lately about LTR (lower than resonant)
> capacitors. This term does not make sense to me. Any capacitor in combination
> with an inductor will form a tank circuit which will resonate at a frequency
> determined by the values of the L and C. Is LTR refering to some sort of
> stagger tuning where the primary tank circuit is resonant at a slightly
> different frequency than the secondary tank circuit? If so, to what end? In
> either case, a common suggestion that is offered to achieve this "LTR" is to
> use a slightly smaller or larger capacitor than one would normally use. The
> same result could be achieved by merely changing the tap position on the
> primary inductor rather than going to the trouble of changing the capacitor.
> Another reason often cited for using this "LTR" value of capacitance is
that it
> lowers the peak voltage that the capacitor is exposed to. This does not make
> sense to me either. The resonant frequency of the tank circuit should have
> little effect on the voltage passing through the tank circuit. If stagger
> tuning is being referred to, then there may be some rationale here. Any
> insights?