[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: [TCML] TC Newbie



According to my sources, dielectric constant of PET is 4.0, while polypropylene (PP) is 2.25.  So from that perspective, PET is superior.

But the more significant measure of merit for a capacitor dielectric (and often overlooked by newbies) is dissipation factor - how lossy it will be.  At 1 MHz, PP is 0.5, while PET is 20.  Higher numbers are bad here.  The Azom.com table you cite for PET indicates a very low dissipation factor at 1Khz, but no mention of 1MHz.  Being in the Mylar family, this is not surprising.

Regards, Gary Lau
MA, USA

> -----Original Message-----
> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> Behalf Of Dave Halliday
> Sent: Monday, December 08, 2008 2:00 AM
> To: 'Tesla Coil Mailing List'
> Subject: RE: [TCML] TC Newbie
>
> Probably meant PET or Polyethylene terephthalate - soda pop bottles.
>
> http://en.wikipedia.org/wiki/Polyethylene_terephthalate
>
> Has a dielectric constant of 3.0 - not good...
>
> http://www.azom.com/details.asp?ArticleID=2047
>
> Dave
>
> > -----Original Message-----
> > From: tesla-bounces@xxxxxxxxxx
> > [mailto:tesla-bounces@xxxxxxxxxx] On Behalf Of David Rieben
> > Sent: Sunday, December 07, 2008 5:41 AM
> > To: Tesla Coil Mailing List
> > Subject: Re: [TCML] TC Newbie
> >
> > Hi Gary, all,
> >
> > I'm afraid that I don't recognize the acronym "PETA"
> > in reference to plactic. The only thing that I can think
> > of for this one is "(p)eople for the (e)thical (t)reatment
> > of (a)nimals" ;^) I know "PE" is polyethylene and HDPE
> > is high density polyethylene but I just can't figure out
> > what the "TA" means. Someone please enlighten me :^?
> >
> > David
> >
> >
> > ----- Original Message -----
> > From: "Lau, Gary" <Gary.Lau@xxxxxx>
> > To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
> > Sent: Saturday, December 06, 2008 11:25 AM
> > Subject: RE: [TCML] TC Newbie
> >
> >
> > PETA is a very lossy dielectric.  But even beyond that, I
> > think that plastic
> > bottles are not a good choice for bottle caps.  Any time
> > there is corona,
> > visible or not, that will rapidly degrade and melt a plastic
> > dielectric and
> > result in a puncture, and that is true regardless of whether
> > or not the
> > plastic is a lossy dielectric.  Glass is much more resistant
> > to corona than
> > plastic, so glass bottle caps can survive even with corona.
> > Corona is the
> > reason that commercial plastic dielectric HV caps are
> > constructed as many
> > lower voltage units in series - so that the voltage across
> > each section will
> > be below the "corona inception voltage".
> >
> > Regards, Gary Lau
> > MA, USA
> >
> > > -----Original Message-----
> > > From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> > > Behalf Of Jim Mora
> > > Sent: Saturday, December 06, 2008 1:25 AM
> > > To: 'Tesla Coil Mailing List'
> > > Subject: RE: [TCML] TC Newbie
> > >
> > > Hello,
> > >
> > > I wonder if 1 or 2 liter PETE coke (or whatever) clear
> > plastic bottles
> > > could
> > > be used. PETE has a very high dielectric strength and
> > puncture resistance
> > > and is thin enough to really raise the capacitance and
> > lower the weight a
> > > bit. Maybe PE bottles which are thicker though.
> > >
> > > Jim Mora
> >
> > _______________________________________________
> > Tesla mailing list
> > Tesla@xxxxxxxxxxxxxx
> > http://www.pupman.com/mailman/listinfo/tesla
> >
> > _______________________________________________
> > Tesla mailing list
> > Tesla@xxxxxxxxxxxxxx
> > http://www.pupman.com/mailman/listinfo/tesla
>
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla