Hi all,
I have 2 resistor like on schematic and I want to measure measuring temperature on Pt100. Trough resistors flow constant current of 0.5mA. I want to amplify voltage drop on pt100 and connect that on ADC. What is the best way to amplify a little voltage change on pt100 ?

 

Hello,

Do you know the temperature influence on the PT100 is not completely linear?

http://zone.ni.com/devzone/cda/tut/p/id/3643

Here is a page from the EDUCYPEDIA with information on the PT100 and circuits for it:
http://www.educypedia.be/electronics/sensorstemprtd.htm

Bertus

 

Also, careful work usually demands a four-wire measurement of the PRT's resistance.

 

An op amp or instrumental amplifier will increase the minute changes to more manageable changes.

What are you trying to measure? (Object and temperatures) This may not be the best for the job.

 

Hello,

Do you know the temperature influence on the PT100 is not completely linear?

http://zone.ni.com/devzone/cda/tut/p/id/3643

Here is a page from the EDUCYPEDIA with information on the PT100 and circuits for it:
http://www.educypedia.be/electronics/sensorstemprtd.htm

Bertus

I will use pt100 in for temperature from 0°C to 50°C. I read somewhere that I can assume that pt100 is enough linear in area. is that true?

 

Is this like a school project and you have to use a PT100 element, or can you use other solutions. Do not be afraid to say this is a school project. Everyone is entitled to help in this forum

 

In the off chance this is not an assignment, you could consider an LM35 - http://www.national.com/mpf/LM/LM35.html#Overview

It is linear in that range and requires much less circuitry to get a useful output.

 

I did a search on Google for pt100. Many good hits on that subject

 

If you are using a microcontroller, then also consider digital solutions like the TMP100 or TMP112. Accurate and easy, just need to do SPI communications.

 

Is this like a school project and you have to use a PT100 element, or can you use other solutions. Do not be afraid to say this is a school project. Everyone is entitled to help in this forum

Yes, I must use pt100. But thanks everyone for other advice

 

http://circuits.linear.com/217
http://circuits.linear.com/215
http://circuits.linear.com/208
http://cds.linear.com/docs/LT Magazine/LT1880_0501_Mag.pdf
http://www.eesensors.com/DocsPDFs/ESP18_RTD2.pdf
http://ww1.microchip.com/downloads/en/AppNotes/00687c.pdf

Keywords for google: rtd signal conditioner pt100 application note