For learning purposes. This is an AMP-OP inverter. You can control the Gian from the two potentiometer following the formula GAIN=-Rf/R1 . This amp can get up to 15V. the Rf potentiometer (feedback) is the one positioned vertically. The R1 is the one positioned orizontally. From the - terminal to de + terminal it is supposed to be 0 Voltage, in this war the gain only depends on the two potentiometer