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which differential amplifier can i use to amplify a low voltage input

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lordmag

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hi ,
here i want to measure the current Im by using a shunt resistor with low value to have this measure i should amplify the voltage between this shunt resistor so we have a low differential input voltage
In my application system the output voltage must be between [2v , 10v] so which amplifier can i choose to solve this problem and thank you for help :))
 

- Vs2 must be between [2V to 10 V]
 

I made a current sensor using a 741 op amp, as a differential amplifier.

I tried putting the sense resistor on the positive side of the load (as in your schematic). However I found it performed better when I put the sense resistor on the ground side of the load. Reading minute voltages could be done more consistently when the input was referenced to ground.

My sense resistor consisted of several inches of 14 ga. wire. It had to carry several amps. I made it just high enough resistance so that it would generate a measurable voltage for the op amp to detect. After some experimentation I found a suitable voltage was several mV when maximum current was going through it.

I amplified it several hundred times so that the output gave me a range between 0.1 V and 9V.
 
thanks
so can you propose me which resistor shunt can i use in this schematic :) i m still newbie at electronic circuit :/
 

The sense resistor should be high enough ohms that you can get a readable voltage across it...

And low enough ohms so as not to impinge on the operation of what you're measuring.
 

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