TIPD209: thermocouple cold junction compensation below 0 celsius cold junction temperature

Hi Mehmet,

it's explained here:

www.ti.com/.../tiduba5

Kai

Hi,
Thank you for answer. I am little confused after reading document :) and I have some questions.
The document says below;
• –50°C to +500°C hot-junction temperature
• 0°C to 75°C cold-junction temperature
Is this range (0°C to 75°C cold-junction temperature) just a testing range? Or given circuit configuration only used above 0°C ?
I have one more question. The document says below;
" Vtc was swept from –2.431 mV to
+27.393 mV, which corresponds to the voltage produced by the thermocouple with a hot-junction
temperature ranging from –50 °C to +500°C, and a cold-junction temperature of 0°C."
–2.431 mV to +27.393 mV voltage range is very narrow range for a thermocouple, am I right? Can you specify what kind of thermocouple is used for tests?
Regards,
Mehmet.

Hi Mehmet,

the cold junction compensation is needed to make your meter work properly independent of ambient temperature.

I think a type J thermocouple is used in the appnote.

Kai

Thanks kai, for quick answer. Do you have idea about RTD sensor? Is it PT100?