current measurement
Ok, I've got a 0.1ohm 4-terminal sense resistor.
The minimum current I want to measure is 100uA.
I now want to amplify the voltage with a non-inverting amplifier with gain of about 20.
That gives me minimum 200uA, and with the 16bit ADC and 2.5V reference, I can measure voltages as low as 38uV with maximum 3LSB error( which is kinda ok for me).
But when I run the circuit through LTSpice, then the circuit only 'works' for currents of about 20mA and higher. Is this because of the spice OPAMP module(generic) that I use?
If I use lower currents in spice, then the output is to high.
Any suggestions?
What about instrumentation amplifier in place of non-inverting amp?