On Sunday 06 December 2015 22:57:52 Rafael wrote:

> On 12/06/2015 07:25 PM, Gene Heskett wrote:
> > Greetings all;
> >
> > Before tv's lost their crt's, there was a component in the power
> > inlet circuit that had a very high negative temp coefficient, which
> > was used to create a high voltage drop when it was cold, which in
> > turn forced the first few seconds of its power draw after being
> > turned on, thru the degaussing coils wrapped around the crt in order
> > to demagnetise it.
> >
> > That voltage drop heated it, and it got hot enough to get down to
> > just a couple of ohms, which was not enough to overcome the MOV in
> > series with the coils.  This also allowed the tv itself to be
> > soft-started, and it worked so well that it was often the major part
> > failure in the tv for the first 3 or 4 years.
> >
> > About 3 or 4 of those, wired in parallel, would also serve as an
> > inrush limiter when I turn on the power supply for my G0704 mill. 
> > But the parts houses we had locally have all evaporated.  I just
> > checked a couple surplus places without finding any of those
> > critters.
> >
> > Does anyone have a suggestion as to where a small handfull of these
> > could be sourced?  Usually bare, they look like a graphite quarter
> > coin with a lead wire soldered to the middle of a silver plated dot
> > in the middle of each face.  Usually slightly thicker than a
> > 'merican quarter.
>
> I think you are looking for NTC (Negative Temperature Coefficient).
> Search brings back numerous links to choose from. However, there are
> better solutions but cost a bit more of course.

Yes, and contrary to a previous poster, the name isn't a Surgistor, but 
a "Thermistor" for the NTC component.

> Here is an excellent article/solution I found searching for "inrush
> current limiter":
> http://www.edn.com/design/analog/4316203/Simple-and-effective-inrush-c
>urrent-limiter-stops-surges
>
Unforch, they do not seem to want to feed iceweasel the pdf.

> Circuit is simple enough to implement it on a generic experimental
> board.

Left coast. I assume you are getting in practice at ducking behind 
something solid. :)

Thanks Rafael.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

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