Thermistor is a semiconductor device whose temperature coefficient of resistance is:
A. Large and negative
B. Small and negative
C. Large and positive
D. Small and positive

Hint:We know that thermistors are used to indicate the change in temperature. Generally, they are made of semiconductor materials. By changing its resistance with respect to temperature, it detects the change in temperature. So the trend in which the resistance changes with temperature will help us to determine the answer of this question.

Complete answer:
We know that a thermistor is a semiconductor made of ceramic materials and it reacts like a resistor which is sensitive to temperature. Usually, thermistors have a high negative temperature coefficient, which means that their resistance increases as temperature decreases, and vice versa.

Also, Thermistors are temperature-dependent resistances which are constructed from metal oxides. The resistance change with temperature is high compared with the metallic resistances, and is usually negative: the resistance decreases with temperature increase.From this, it is clear that thermistor is a semiconductor device whose temperature coefficient of resistance is large and negative.

Hence, option A is the right answer.

Note:In other words, we can say that the Thermistor is a type of resistor whose resistance changes rapidly with the small change in temperature. Thus, it is a type of resistor in which the flow of electric current changes rapidly with small change in temperature. It is also interesting to know that the word thermistor is derived from the combination of words “thermal” and “resistor”.