RRB Technician Grade 1 Model Paper 4

Concept:A thermistor is a temperature-sensitive resistor whose resistance changes with temperature.Explanation:The word thermistor comes from "thermal" and "resistor".Thermistors are made from semiconductor materials.They have a negative temperature coefficient of resistance.This means resistance decreases when temperature increases.They can measure temperatures from $-100^\circ C$ to $300^\circ C$.Their sensitivity is about $10\ \Omega/^\circ C$.As temperature rises, more charge carriers become available, so resistance falls.Answer:The correct option is C. negative temperature coefficient.