[sci.electronics] linearised thermistor

enenkel@cs.toronto.edu (Robert Frederick Enenkel) (08/27/90)

I heard that YSI makes a "linearised thermistor", which is a thermistor
packaged with a resistor network in such a way that the resulting resistance
is linear with temperature.  Does anyone know what this resistor network
looks like?    Robert Enenkel (enenkel@na.toronto.edu)

larry@kitty.UUCP (Larry Lippman) (08/28/90)

In article <90Aug27.123035edt.501@smoke.cs.toronto.edu>, enenkel@cs.toronto.edu (Robert Frederick Enenkel) writes:
> I heard that YSI makes a "linearised thermistor", which is a thermistor
> packaged with a resistor network in such a way that the resulting resistance
> is linear with temperature.  Does anyone know what this resistor network
> looks like?

	YSI (Yellow Springs Instrument) has two varieties of "linearized"
thermistors: (1) a 3-terminal two-element device; and (2) a 4-terminal
three-element device.  Device (1) has two thermistors with one common
wire, and device (2) has three thermistors with one common wire.

	There are two types of application circuits for *each* device:
(1) linear voltage vs temperature; and (2) linear resistance vs temperature.
These application circuits are all passive with resistor elements only,
but are too complex to illustrate in this forum.

	I'm certain that YSI will gladly send you application data on their
products.

	I have used YSI products with good results (i.e., as good as a
thermistor can be).  However, I really don't care much for thermistors,
and would recommend an RTD instead - unless you have a size or cost
problem.

Larry Lippman @ Recognition Research Corp.  "Have you hugged your cat today?"
VOICE: 716/688-1231   {boulder, rutgers, watmath}!ub!kitty!larry
FAX:   716/741-9635                  {utzoo, uunet}!/      \aerion!larry

vail@tegra.COM (Johnathan Vail) (08/29/90)

In article <90Aug27.123035edt.501@smoke.cs.toronto.edu> enenkel@cs.toronto.edu (Robert Frederick Enenkel) writes:

   I heard that YSI makes a "linearised thermistor", which is a thermistor
   packaged with a resistor network in such a way that the resulting resistance
   is linear with temperature.  Does anyone know what this resistor network
   looks like?    Robert Enenkel (enenkel@na.toronto.edu)

I don't think that it is that easy.  The linear temprature transducers
I have seen were active devices, I think.  Not only the thermistor but
some kind of log amp and network that compensated.  It was still
convenient and the size of a small transistor.


"Did you ever walk into a room and forget why you walked in?  I think
that's how dogs spend their lives." -- Sue Murphy
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