Patent ID: 7777565

Claim:
A differential amplification circuit comprising: an operational amplifier having a potential at an output terminal thereof handled as an output potential; a first resistor connected between a first input terminal brought to a first input potential and an inverting input terminal of the operational amplifier and the first resistor functioning as an input resistor; a second resistor connected between a second input terminal brought to a second input potential and a non-inverting input terminal of the operational amplifier and the second resistor functioning as an input resistor; a third resistor connected to the inverting input terminal of the operational amplifier; a fourth resistor connected to the non-inverting input terminal of the operational amplifier; a fifth resistor connected in series with the third resistor between the third resistor and the output terminal of the operational amplifier; a sixth resistor connected in series with the fourth resistor between the fourth resistor and a reference potential point; and a seventh resistor connected between the junction of the third and fifth resistors and the junction of the fourth and sixth resistors, wherein: in a state in which the first and second input terminals are brought to the same potential and the potentials at the first and second input terminals are set to a potential different from the reference potential, the resistance value of any of the first, second, third, fourth, fifth, and sixth resistors is adjusted so that the output potential and reference potential will be substantially equal to each other.