At 25C, an RTD has a resistance of 500 2 and a dissipation constant of PD-50 mW/C. Temperature coefficient of resistance of RTD is a,-0.0039 C. This RTD is used in a bridge circuit as shown in the Figure Q. 3, with R = R = 500 and R3 a variable resistor used to balance the bridge. If the supply is 12 V and the RTD is placed in a bath at 0C, find the value of R3 to null the bridge - [5] (a) Without the self-heating effect, (b) With the self-heating effect. www R2 R1 1 12 V RTD R4 ww