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very high precision ADC for whetston bridge

Question asked by asadi.siyavash on Sep 18, 2013
Latest reply on Sep 24, 2013 by ChrisD.Rama

Hi,

I want to read voltage of whetstone bridge by using ADC+internal PGA like AD7730 but my problem is our strain gauge sensitivity is 100uV/V and  strain gauge's supportable excitation voltage is 0.1Volt and we need atleast 10bits resolution so This requires a stable reading of 10uV/1024 or 10nV

by my calculating I know reaching to exactly  24 bit is big mistake, especially in my case that the excitation is very low, I think I should change my way and I need at first precision instrument amplifier with fix gain that magnitude bridge output and then I use AD7730, is it true? and what do you suggest me? or Analog Devices have better solution and IC

any help would be greatly appreciated,

Sincerely yours,

Siyavash.

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