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Entry  Thu Aug 10 14:13:23 2017, Kira, Summary, PEM, temperature sensor IMG_20170810_121637~2.jpgIMG_20170810_134422~2.jpg
    Reply  Thu Aug 10 21:22:06 2017, rana, Summary, PEM, temperature sensor tempsensnoise2.pdftempnoise_final.pdf
Message ID: 13183     Entry time: Thu Aug 10 14:13:23 2017     Reply to this: 13188
Author: Kira 
Type: Summary 
Category: PEM 
Subject: temperature sensor 

Goal is to build a temperature sensor accurate to 1 mK. Schematic is shown below. This does not take into account the DC gain that occurs.

Parts that would be used for this: LM317 regulator, AD592 temperature transducer, OP amp (low input noise and high impedance), 100K (or maybe 10k) resistor. This is what is currently proposed, but the exact parts we use could be changed to better fit the sensor. The resistor and the OP amp will be decided depending on the output of the AD592.

Once this is built, I would like to create a few copies of it and put them into an insulated container and measure the output from each one. This would allow us to calculate the temperature noise of the circuit, as we can take out the variations due to temperature changes inside the container by comparing the outputs.

I can also model the noise in the circuit to see how much noise there is before building it. There are three terms to the noise that we have, and we need to decide which one dominates at low frequencies.

Our final goal is to create an additional circuit that could cancel out the DC gain. I have attached an additional schematic proposed by Rana that would help with this issue. I will leave this second half for when the first part works.

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