Op Amp current sense ..

Thread Starter

toffee_pie

Joined Oct 31, 2009
235
Hi Guys,

I have a INA999 with a gain of 100 and Rsense is 2mOhm, trying to work out the output current, Vref is 1.25V.

I have tried this Vout = 1.25+100 * (Rsense * I) - however measuring Vout the current is incorrect.

Using the voltage drop across the sense resistor I can get better readings but want to get output from the op amp as it its going to the ADC so should be more accurate.

any thoughts?
 

AlbertHall

Joined Jun 4, 2014
12,345
So what current did you put in and what voltage did you get out?
How does the output voltage change with different currents (including zero current)?
A schematic would be helpful.
 
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