Re: Filters & Chokes

["Jim Lux" <jimlux-at-xxxxxxxxxxxxx> (by way of Terry Fritz <twftesla-at-xxxxxxxxxx>)]

Nope... copper sulfate and water works quite well and can give nice
resistance ranges in reasonable sizes.  The real problem is heat
dissipation.  Most electrically insulating tubes are also good thermal
insulators, so getting the heat out of the water is a problem.  Great for
pulsed duty though.


A 0.1 Mol (16g/liter) solution is around 40K for 1 meter long by 0.32 sq cm
(1/4" ID).  If you needed a 10K resistor, you could either go to 25 cm of
1/4" tubing, or to a meter of 1/2" ID tubing, or 4 lengths of 1/4" in
parallel.  (depends on power dissipation, really).

If you need real low resistances, in the tens of ohms, this might not be
the best scheme.  For high resistances, you can reduce the concentration of
salt.  There is a limit, though.

Tesla list wrote:
> 
> Original poster: "acmnovak" <acmnovak-at-email.msn-dot-com>
> 
> Jim-
> Don't those have to be quite large in order to be effective?
> I am considering testing out a glass tube filled with a solution of
> saltwater (maybe like a ratio of  1 liter of water to .1 gram of salt), and
> then using aluminum bolts in rubber stoppers at each end. I'll try and do
> some testing with these at around 2kW and we'll see how they hold up.... man
> i need a infrared thermometer.
> My 1 cent...
> 
> -Michael
> 
> ----- Original Message -----
> From: Tesla list <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Monday, November 13, 2000 6:46 PM
> Subject: Re: Filters & Chokes
> 
> > Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net>
> >
> > Use a salt water resistor. Cheap, high power dissipation capability, etc.
> > http://home.earthlink-dot-net/~jimlux/hv/rwater.htm
> >
> >
> > Tesla list wrote:
> > >
> > > Original poster: "Neil Chambers" <Neil_Chambers-at-paragon-it-dot-com>
> > >
> > > Cripes
> > >
> > > I'm just costing out the filter as per Terry's circuit diagram
> > > (http://hot-streamer-dot-com/TeslaCoils/Misc/NSTFilt.jpg) and at the UK
> prices
> > > I've found, it's gonna set me back over £110! £80 of that being the 100W
> > > wire-wound resisters.
> > >
> > > Any cheaper options?!
> > >
> > > Cheers
> > >
> > > neil
> >
> >
> >
> >