I have a hall effect sensor that is going to read 0 to 25 amps. The hall effect sensor has an output of Vs/2. I plan on using 5 Vdc for VS. This gives a null offset output of 2.5 Vdc at 0 amps of current. The sensor sensitivity is 37mA/1A. At 25 amps this would give a sensor output of 3.425 Vdc. Per my attached schematic, I am trying to offset the 2.5 Vdc with U1 to get a 0 Vdc output, and then adjust gain to get a 0 to 5 Vdc output. U2 is being used as a buffer and the 0 to 5 Vdc wil then be used as an analog input on my Arduino. I have learned/refreshed myself alot on op amps in the last 5 hours and cannot get this to work/an not totally sure what I am doing. I can never get the output at 0 or even close when I have a 2.5 Vdc input on U1 (0 amps from the sensor). I keep ending up with 2.5 Vdc output at U2 and U1 in this case. Any help would be appreciated.
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