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Forum: µC & Digital Electronics What is under the hood and how different temperature sensors work?


Author: Mozo Bata (Company: OMOS) (mozobata)
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There are a lot of different types of temperature sensors for various 
applications. I am mostly interested in human body temperature 
measurement.

After some reading I'vee been able to distinguish three groups of 
sensors:

    analog (like TMP36)
    digital (like DS18B20:)here is the datesheet of 
DS18B20:http://www.componentschip.com/details/Maxim-Integr...

    infrared (like MLX90614)

While I understand the difference in measurement type/methodology, 
accuracy and communication I am not sure how they work under the hood. 
I've been trying to understand schematics in documentations but because 
I haven't got lot of experience in that matter I failed.

What I've found out or what I feel about this sensors is:

    analog sensors are using some kind of temperature variable 
transistor/resistor to get readings value.
    infrared sensors use infrared detection to determine the 
temperature. This sensor is I guess the easiest to understand because 
heat emits some kind of infrared and the point here is just to detect 
how much of this light is emitted.

I have no idea how does digital works.

Can someone please give me maybe more complex explanation of this 
sensors, the best would be with some references.

Author: Lothar Miller (lkmiller) (Moderator)
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Mozo B. wrote:
> I have no idea how does digital works.
As temperature is an analog value under the hood every temperatur has an 
anlog frontend.

And after getting an analog temperature value out of this, there may 
follow an AD converter with an interface to form a digital temperatur 
sensor.

Thats all.

: Edited by Moderator

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