Device for correcting the non-linear variation of a signal as a function of a measured magnitude

Claim 1

In an electrical measuring system comprising a resistance bridge type measuring circuit; power supply inputs at one pair of diagonally opposite points of said bridge circuit; first and second signal outputs of said bridge circuit; a power supply; conductors connecting said power supply to said power supply inputs of said bridge circuit; a measuring probe, the electrical resistance of which is sensitive to the variation of a physical quantity to be measured; further conductors connecting said probe to said first signal output and to one of said power supply inputs; an operational amplifier; a positive input of said operational amplifier; an output of said operational amplifier; an electrical connection between said first bridge circuit output and said positive input of said operational amplifier, wherein, in order to correct the error due to the non-linear variation of the output signal of the system, the improvement comprises an electrically resistive element connected, on the one side, to said operational amplifier outPut and, on the other side, directly to a point on the electrical path between said probe connection and said positive input of said operational amplifier via said first bridge circuit output, the ohmic value of said electrically resistive element being effective to produce a correcting potential difference which is fed back to said positive input of said operational amplifier, said correcting potential difference being proportional to the amplifier output signal, the maximum value of said correcting potential difference compensating the maximum value of error to be corrected in the range of measurement considered.