RE: "Warming Up"

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Lau, Gary" <Gary.Lau@xxxxxx>

The graph indicated "DC", but I would guess the tempco is similar across
the board.  If one takes any ceramic cap, like a ceramic disk, hook it
up to a capacitance meter, and briefly pass a match under it - you'll
get the idea.

Regards, Gary Lau
MA, USA

> -----Original Message-----
> From: Tesla list [mailto:tesla@xxxxxxxxxx]
> Sent: Saturday, February 18, 2006 1:40 AM
> To: tesla@xxxxxxxxxx
> Subject: Re: "Warming Up"
>
> Original poster: "D.C. Cox" <resonance@xxxxxxxxxx>
>
>
> Did they indicate if it was a test at RF frequencies or at DC?
>
> Dr. Resonance
>
>
> >Original poster: "Lau, Gary" <Gary.Lau@xxxxxx>
> >I just looked up the spec sheet for TDK doorknob caps.  They make two
> >types:
> >UHV series w/ Z5T dielectric, and FHV series w/ Y5S dielectric.
> >Eyeballing the chart,
> >Over a range of 0-50*C, the UHV capacitance changed 28%.
> >Over a range of 0-50*C, the FHV capacitance changed 15%.
> >Regards, Gary Lau
> >MA, USA
> >
> > > Original poster: "C. Sibley" <a37chevy@xxxxxxxxx>
> > >
> > > Hey Gary,
> > >
> > > You pegged it, I'm using Doorknobs and they do get
> > > warmer when running...
> > >
> > > The effect seems to also be less noticeable if the
> > > gaps are freshly cleaned.  Might be an effect of one
> > > or more variables...
> > >
> > > Thanks,
> > >
> > > Curt.
> > >
> > >
> > > --- Tesla list <tesla@xxxxxxxxxx> wrote:
> > >
> > >  > Original poster: "Lau, Gary" <Gary.Lau@xxxxxx>
> > >  >
> > >  > Ceramic caps, i.e. doorknob caps, will vary their
> > >  > capacitance with
> > >  > temperature.  What kind of caps do you have?  Do
> > >  > they feel perceptibly
> > >  > warmer after use?
> > >  >
> > >  > Gary Lau
> > >  > MA, USA
> > >  >
> > >  >
> > >  >  > Original poster: "C. Sibley" <a37chevy@xxxxxxxxx>
> > >  >  >
> > >  >  > I've noticed that my 60mA NST powered coil gets a
> > >  >  > significantly longer spark after running 15-20
> > >  >  > seconds.  After it "Warms Up" it starts at full
> > >  > power,
> > >  >  > but if it's been sitting for a day it begins at
> > >  > less
> > >  >  > than a third of the spark length.
> > >  >  >
> > >  >  > I assume it's out of tune when it's "Cold", do
> > >  > you
> > >  >  > think this phenominom coukd be related to the
> > >  >  > capacitors?  I seem to recall hearing once that
> > >  >  > capacitors could change capacity significantly
> > >  > with
> > >  >  > temperature...
> > >  >  >
> > >  >  > Curt.
> > >  >  >
> > >  >
> > >  >
> > >
>
>