connecting PT100 to uController

Discussion in 'The Projects Forum' started by eric_s88, Nov 6, 2013.

Apr 20, 2011
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1
Hi everybody

I'm going to measure a surface temperature with pt100. what I got from this sensor is that, its resistance varies with the temperature. and the "100" stands for 100 $\Omega$resistance in 0 degrees. and should have a current source to transform the resistance to a voltage and feed this to uC adc. (10bit)

my problem is how to design current source ? would it be right to use current source ICs ? and how much big should be that current ?

thank you

2. MikeML AAC Fanatic!

Oct 2, 2009
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Here is something I did years ago: (never throw anything away). Stare at it for a while, and come back if there is something you dont understand.

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3. Dodgydave AAC Fanatic!

Jun 22, 2012
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one here for an Arduino..

eric_s88 likes this.
4. MikeML AAC Fanatic!

Oct 2, 2009
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I question why, in that circuit, they start with the bridge unbalanced?

5. Dodgydave AAC Fanatic!

Jun 22, 2012
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Maybe starting at a different temperature than yours, alter the bridge resistors to suit your design