Patent ID: 6845659

Claim:
A sensor, comprising: a first amplifier having a first input, a second input, and an output; a first resistor electrically connected in series with a first variable resistor between the output of the first amplifier and a reference terminal, the first resistor being electrically connected between the first input of the first amplifier and the output of the first amplifier, and the first variable resistor being electrically connected between the first resistor and the reference terminal; a second amplifier having a first input, a second input, and an output; a second resistor electrically connected in series with a second variable resistor between the output of the second amplifier and the reference terminal, the second resistor being electrically connected between the first input of the second amplifier and the output of the second amplifier, and the second variable resistor being electrically connected between the second resistor and the reference terminal; and a voltage divider having an input that is switchably connected to one of the output of the first amplifier and the output of the second amplifier, and an output that is switchably connected to one of the second input of the first amplifier and the second input of the second amplifier, the output of the voltage divider setting a resistance of the first variable resistor when the input of the voltage divider is connected to the output of the first amplifier and the output of the voltage divider is connected to the second input of the first amplifier, and setting a resistance of the second variable resistor when the input of the voltage divider is connected to the output of the second amplifier and the output of the voltage divider is connected to the second input of the second amplifier.