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From: Bill Sloman <bill.sloman@ieee.org>
Newsgroups: sci.electronics.design
Subject: Re: Converting a NTC voltage into temperature in Celcius
Date: Fri, 11 Apr 2025 16:13:07 +1000
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On 11/04/2025 2:49 am, Don wrote:
> brian wrote:
> 
> <snip>
> 
>> I ended up using a diode as a temperature sensor as I
>> couldn't get it linear enough.
> 
> Interesting. Thank you for sharing. When operated in Zener mode (as
> opposed to avalanche mode) a Zener diode's NTC apparently remains
> approximately the same, regardless of orientation (forward or reverse
> biased).

Whether a reverse biased diode breaks down in Zener mode or avalanche 
mode depends entirely on the diode you have selected.

if it breaks down at less than 5V reverse voltage it is breaking down by 
the Zener mechanism (with a negative temperature coefficient) , and if 
it the breaks down at an 8V or a higher reverse voltage the avalanche 
mechanism is dominant (with a positive temperature coefficient.

https://toshiba.semicon-storage.com/us/semiconductor/knowledge/faq/diode/are-there-any-special-considerations-for-the-temperature-coeffic.html

doesn't exactly conform to your claim.

-- 
Bill Sloman, Sydney