Patent ID: 6795783
Filing Date: 2004-09-21
Classification: G01R

Abstract:
A method of accurately measuring the varying resistance of a sensing resistor, that comprises, alternately applying from a programmable current source pairs of different currents to each of a sensing resistor and a standard reference resistor to develop corresponding pairs of different voltages; subtracting the different voltages of the respective pairs of different voltages; subtracting the different currents of the respective pairs of currents applied to the respective resistors; and taking the ratio of the subtracted pairs of different voltages each divided by the corresponding subtracted differences in the currents of the respective pairs of currents, wherein the currents applied to the sensing resistor are applied through an offset resistor and wherein the location of the sensing resistor is in equipment such as vehicular equipment that does not permit full physical access to both terminals of the sensing resistor, and wherein the sensing resistor comprises a parameter-measuring resistance, the ground terminal of which is in an equipment location not easily accessible.