I'm trying to measure the current through a 1 milli ohm shunt resitor, I need a resolution of at least 250mA but I only have some op 07, I'm from Venezuela an here its pretty hard to find components, the best I could find was the op07 and the 1milli ohm shunt, it's feasible to do wthat I need? the resistence of any wire is bigger than the resistence of the shunt so I can't use the op as an non inverting, the wire resistence will give me an offset of what I have any control, I'm thinking to use three amplifiers to get a diferential input. There is a better way to approach this problem? I would do it with regular 5% resistance, I can allow an error of about 10-15% I have already tested the circuit suggested by Spehro Pefhany, I have to use potentiometers to get the values of resistors.
I have already tested the circuit suggested by Spehro Pefhany, I have to use potentiometers to get the values of resistors.
The first two values are quite far from each other , I'm thinking in take the median and used to calculate the current, any better sugestion?
The resistance is supposed to be of 1miliohm
I have made more measurements and get very different values, the red ones are with a small load connected between the shunt and ground, I think there is a problem with common mode voltage.