Spehro Pefhany wrote:
> At 08:20 AM 11/18/02 +0000, you wrote:
>
>
>>   You can then select what type of function to fit, linear,
>> polynominal, exponential, log etc.  For a thermistor, a 3rd order or
>> better polynominal does the job very well.  Under the "Options" tab
>> of the trend line menu, check the "Display equation on chart".  You
>> can then use this equation to obtain any arbitrary value.
>
> You must be using the thermistor over a very narrow range, n'est pas?
> (as opposed to the full usable range of the sensor)
>
> I've found even high order polynomials a very poor way of doing R->T
> conversion for thermistors. Breaking it into segments and using
> a number of lower-order polynomials works, however.


Working with this kind of components for long, the easier way is using
table and interpolation. Works like a charm.
Polynomial formulas also work nicely, sometimes just the long math uses
more program memory than the tables, soooo....

Wagner.

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