Question

Consider a thermistor having the following specifications: RF=150kΩ at a reference temperature of 35^oC and temperature coefficient of resistance = 25^oC. Determine the change in resistance at 100^oC.

(a) -1.625MΩ

(b) 9.75MΩ

(c) 4.78MΩ

(d) None of the mentioned

This question was addressed to me during an interview.

The doubt is from Instrumentation Amplifier in portion Operational Amplifier Applications of Linear Integrated Circuits

Answer 1

The correct choice is (a) -1.625MΩ

Let me elaborate: Thermistor has negative temperature coefficient of resistance. Therefore, △R=-(25kΩ/^oC )×(100^oC-35^oC) = -1625kΩ .

△R=-1.625MΩ.