Go Down

Topic: Need to measure -30c to 150c (Read 646 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


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


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


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.


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 will NOT respond to personal messages, I WILL delete them, use the forum please ]


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


Go Up

Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

via Egeo 16
Torino, 10131