I have an H-bridge circuit that is meant to measure the voltage across the shunt (330 resistor) and load (pictured as 4700, but variable) to calculate the resistance of the load (I have added the 10k to lower the voltage across the other two components). The H-bridge reverses the direction of the current every .01 seconds, and the transistors are activated by GPIO pins from a Raspberry Pi. I am measuring the voltage using an ADC differential Pi. (https://www.abelectronics.co.uk/p/65/adc-differential-pi) When measured the voltages across the shunt and the load are not in the same ratio between flips, e.g (0.070984375 V and 1.013546875 V in one direction and 0.0710781250000001 and 1.01421875 V in the other direction).
The voltages being different between different directions is not my issue, so much as the fact that the ratio between the voltages is inconsistent. The voltages in a given direction are consistent between handheld voltmeters and multiple ADC boards that are run using the Pi. I have tried changing the base resistors for all four transistors and changing the input voltage but nothing fixes the problem.