In article t, msg wrote:
Greetings,

I'm working up a demonstration of an antique electronic temperature
controller which needs a sensor with a PTC of about 5 to 6 ohms/degree F
average (at 20 degrees C); nickel-iron resistance wire fits the bill
fairly well, and I would like to find a coil on a low-mass substrate,
like ceramic, of roughly 1150 ohms at 20 degrees C, hopefully no more
than a few inches long (up to 5 inches is OK). I have some resistance
wire salvaged from old soldering iron heater cores, but its gauge is
a bit large such that to get 1150 ohms would require quite a lot of it
on a rather large form.

Perhaps someone has recollections of small assemblies of resistance wire
either used for heating, in the 10 to 12 Watt (at 120 VAC) range, or
for sensing, that might come in at around 1150 ohms, so that I might
avoid a tedious winding of hair-fine wire under magnification.
Surprisingly (to me), my cannibalization of some 10 Watt heating tools
(like hot melt glue guns) revealed not resistance wire, but some form
of semiconductor with a NTC (isn't thermal runaway an issue here?).


I don't know your linearity requirments. I might suggest using a thermsiter.
The only thing I know of, 1 K are hard to find, are some SMT thermisters.
I had used one soldeing leads on to it. Typical 1097 ohms @ 25C
You can add series resistanc eto calibrate scale. Linearity might
be off which is gain of device.

http://www.vishay.com/docs/28762/28762.pdf



greg