Part Number:OPA548EVM
I’ve setup the OPA548EVM with dual power supplies (+/- 12VDC) and input signals using the differential amplifier setup in the user manual, Figure 8, shown below. I have J2 (Vin-) as a 20Hz 1Vp-p sine wave and J5 (Vin+) as a +3V DC signal. What is the equation to set the gain for this circuit? I want to amplify Vout as the difference between the inputs on J2 & J5. Can I replace the surface mount resistor at R2 with a 10kOhm potentiometer (wired to the pads) to vary the resistance and increase the gain as R1/R2 or do I need to vary both R2 and R5 together via one potentiometer? Alternatively, would it be better to increase R1 using a different Pot (say 100kOhm)?
Thanks.
