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Ceramic core resistors

Terry, Gary, list,
Well I now have some ceramic resistors from some surplus stuff.
So I am not going to build some bombs with the others :)
they are 4700 Ohm 25 Watts, I have 12 to be exact...
I asked some friends on series and paralleling resistors to achieve
higher values, but nobody seems to remember the rules...
school time is far away and I can't find my old books :<
So my question is what are the rules to use some resistors
in the form of a multi resistors net ? (like mmcs)
Series = more ohms ?
Parallel = more watts ?
another question I have, is were to recover som MOVs ...
I cannot order from digikey... too much money for a poor order,
as I live in Italy. Is there any apparatus to dismantle to find some ?
I mean rated 1800 Volts.

Ciao all
Tnx again

-----Original Message-----
From: Tesla List <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: marted́ 6 giugno 2000 7.31
Subject: RE: FILT1.JPG (Was Terry's NST Filter Network)

>Original Poster: Terry Fritz <twftesla-at-uswest-dot-net>
>Hi Gary,
>The file FILT1.jpg was out of date and has been removed.  See:
>I presently use Digi-Key L100J1K0-ND resistors as described at:
>They are Ohmite 100 Watt 6.5 x 0.75 inch vitreous enamel fixed value power
>They have no aluminum heat sinks but are just wire wound on a ceramic core
>under ceramic glazing.  They should easily stand continuous 20+ kV spikes
>across their terminals...
>'Dale' makes similar rated resistors with the gold anodized aluminum heat
>sinks around them.  At work, they blow out like little shotguns...  I have
>a dent in my polycarb S-glasses from one of them turkeys...  Very poor for
>high voltage (any voltage!) especially when Dale screws up and does not
>center the elements in the silicon potting.  Dropping 480V three phase
>across one when the internal element is lying against the aluminum case...
>But "I" don't use them...  Those Ohmite ceramics are the best out there
> Terry