In: Physics
Consider a metal wire that is used as thermistor. When it is connected to a 10.00 V voltage source, at 23.50C a current of 0.4212 A is flowing through the wire. What will the temperature if the current is 0.3818 A. Assume a = 0.00429 (C0)-1
Initial temperature, t1 = 23.50C
Resistance at temperature t1 is R1 = V/I = 10/0.4212 = 23.74 Ω
Resistance at temperature t2 is R2 = V/I = 10/0.3818 = 26.19 Ω
Temperature coefficient of resistance, α = 0.00429 0C-1
The variation of resistance with temperature is given by the relation,
R2 = R1 { 1 + α(t2 – t1)}
26.19 = 23.74 x { 1 + 0.00429(t2 – t1)}
t2 – t1 = 24.05
t2 = 24.05 + t1 = 24.05 + 23.5 = 47.550C
temperature, t2 = 47.550C