A null-type Wheatstone bridge is used to accurately measure the resistance of a nickel resistance thermometer during a calibration procedure. The circuit shown in Fig. 6.1 is used, in which the known...

A null-type Wheatstone bridge is used to accurately measure the resistance of a nickel resistance thermometer during a calibration procedure. The circuit shown in Fig. 6.1 is used, in which the known fixed resistance values are given by R2 ¼ 123.7 U and R3 ¼ 127.4 U. The thermometer is inserted in the circuit as Ru and then the variable resistance box Rv is adjusted until the bridge output voltage Vo goes

to zero. At this balance point, the value of Rv is 117.3 U. Calculate the resistance of

the thermometer.