Go Down

Topic: Need to measure -30c to 150c (Read 485 times) previous topic - next topic

Larry E

Hello Forum, I am in need of some help with measuring very low temperatures.  The LM35 sensor has the range, but from +25c to -55c the output is in negative volts.  How do I deal with this problem.    Thanks for any help, Larry

AWOL

Bias the output so the whole range is positive.
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

Larry E

How would that be done?  Larry

olf2012

Use a TMP36 aka LM50. It does not require a negative supply voltage

KeithRB

A type T or J thermocouple would work, too.

The current requirement is pretty small, 50 uA, so a battery would last a long time.

You could use an Op-Amp to level shift the voltage.

MarkT


How would that be done?  Larry


Erm use the example in the datasheet? Figure 18. http://www.ti.com/lit/ds/symlink/lm35.pdf

The DS18B20 only does -55 to 125C alas.
[ I won't respond to messages, use the forum please ]

Pelleplutt

Use TMP 01 and get the temerature i degrees Kelvin. Zero is realy zero.

Pelle

Go Up