E
expertengr
Guest
I need to invert the polarity of the voltage across PT1000 from -0.548 V to +0.548 V using an OpAmp AD844 in unity gain inverting configuration. The output of the inverting amplifier is Vout = -(R2/R1) Vin, where R2 is the feedback resistance. If I use R1 = R2 = 1K Ohm, the output of the OpAmp is only 0.250 V which shows that gain approximately half instead of 1. In order to get approximately +0.548 V I need to use R2 = 2.2 K Ohm feedback resister. I am wondering why the unity gain does not work to convert -0.548 V to +0.548 V ?