Re: Question about diode temperature and forward voltage


<acataldo@xxxxxxxxx> wrote in message
news:1150247988.008112.28560@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx


** GG.


I'm trying to understand how a diode can be used to detect changes in
temperature. According to all the literature I've read, a diode's
forward voltage, Vf, falls by 2 mV for every 1 degree C increase in
temperature.


** Notice how only one significant digit is given.

Means actual tempco can be between -1.5 and - 2.5 mV per C

A diode needs to be calibrated to use as a thermometer.


This doesn't seem to agree with the diode equation,


** The "diode equation " has NOTHING to do with the matter.

That is a PHYSICS equation for a hypothetical IDEAL diode with NO forward
voltage drop ( hence no forward drop tempco) and no internal resistance or
other imperfections all real diodes have.




........ Phil


.

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