Question

Two materials A and B have resistance temperature coefficients of 0.004 and 0.0004 respectively at a given temperature. In what proportion must A and B be joined in series to produce a circuit having a temperature coefficient of 0.001?

Answer 1

Let R_A and R_B be the resistances of the two wires of materials A and B which are to be connected in series. Their ratio may be found by the simple technique shown in Fig. 1.10.

RB/RA = 0.003/0.0006 = 5

Hence, R_B must be 5 times R_A.