Question

The relative decrease in the electrical resistance of the thermistor is proportional to the increase in temperature.

(a) True

(b) False

I had been asked this question in examination.

My query is from Calorimetric Biosensors in section Biosensors of Enzyme Technology

Answer 1

The correct option is (a) True

Best explanation: The thermistors are used to detect the temperature change. It functions by changing their electrical resistance with the temperature, obeying the following relationship

\(\frac{∆R}{R} = -(\frac{B}{T^2})∆T\)

According to this equation, the relative decrease in the electrical resistance (ΔR/R) of the thermistor is proportional to the increase in temperature (ΔT). A typical proportionality constant (-B/T^2) is -4% /˚C. The resistance change is converted to a proportional voltage change before amplification. The expected result is a linear correlation between the response and the enzyme activity.  Hence the above statement is true.