NTC -  And to think in 1972, I gave up the mundane world of pipes,
reactors, distillation columns and heat exchangers for that new stuff -
building printed circuit boards with dry film photoresist (kind of like
selling sliced bread to the masses who were mixing flour, yeast, eggs and
making their own photoresist).   Boy did I get sucked in.  Have I told you
that DuPont Riston@ celebrated the 50 year invention anniversary this past
April?

On Thu, Jul 19, 2018 at 8:38 AM Stadem, Richard D <[log in to unmask]>
wrote:

> It kept you gainfully employed for decades, and boy we were glad "Doctor
> Capacitance" was always there with the full capacity of answering our
> questions on the subject, with authority.
> Odin
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of John Maxwell
> Sent: Wednesday, July 18, 2018 4:46 PM
> To: [log in to unmask]
> Subject: Re: [TN] capacitor measurement
>
> We need to keep in mind that the dielectric materials are polycrystalline
> semiconductors and do not behave in a linear fashion especially when
> dielectric layers are measured in a couple of microns, that just adds to
> the fun of it all:-) and kept me gainfully employed for decades.
>
> John Maxwell
>
> Sent from my iPhone
>
> > On Jul 18, 2018, at 4:51 PM, John Burke <[log in to unmask]> wrote:
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >        Lol,
> > If your theory is correct the “fluid stream” would follow the laws of
> fluid dynamics which it doesn’t since for the flow (current) to increase
> for a given resistance the pressure (voltage) would have to increase which
> is exactly the opposite of Bernoulli’s laws.
> > And yes an ageing capacitor does resemble a balloon in capacity terms.
> > Best regards.
> > John
> >
> >
> >        Sent from my iPad Pro
> >
> >
> > From: 30171501600n behalf of
> > Sent: Wednesday, July 18, 2018 1:41 PM
> > To: [log in to unmask]
> > Subject: Re: [TN] capacitor measurement Ahhh, those blank, blank
> electrical engineers again.   Why can't it be
> > simple?  Current is a flowing fluid stream, just electrons not water.
> > Resistors are valves that increase or decrease the flow.  Capacitors are
> > tanks where the fluid flow is stored.   And now you are telling me the
> tank
> > size varies with age and temperature.  What are you electrical guys using
> > for a tank - some kind of water balloon or something?
> >
> > On Wed, Jul 18, 2018 at 4:04 PM Wayne Showers <
> [log in to unmask]>
> > wrote:
> >
> >> What has been described is all good information, but here is the yeah
> but:
> >>
> >> At design:
> >> Voltage coefficient is the largest concern and for this reason, each cap
> >> should be overtightened and then loosened.  General Rule I follow in RC
> >> circuits is to try to keep the capacitance as low as possible to
> counteract
> >> the effects of aging.
> >>
> >> In production testing:
> >> So long as the specifications are known, I use a variant of the old
> >> Mil-R-39008 (Carbon Comp Resistors) which is group average of 2X
> tolerance
> >> and for individuals, 3X tolerance.  This has been effective in limiting
> >> both bad product and test failures.  I also target testing at 60Hz for
> >> capacitors to limit capacitance depression from higher frequency and/or
> >> source impedance.
> >> These attributes will limit false rejections at Incoming Inspection and
> >> ICT.
> >>
> >> As for 'refreshing' capacitors:
> >> Baking above the Curie point is not always possible or for that matter
> >> even desirable, so I only ever did this on a limited basis.
> >>
>