Which type of thermistor is typically used as a temperature sensor whose resistance decreases with rising temperature?

• A. NTC thermistor
• B. PTC thermistor
• C. Capacitor
• D. Inductor

Answer: (A)

Understanding how thermistors respond to temperature helps here: a thermistor’s resistance changes with temperature, and there are two common behavior types. An NTC, or Negative Temperature Coefficient thermistor, decreases its resistance as temperature rises, making it ideal for a temperature sensor because you can read temperature from the decreasing resistance in a simple circuit. The alternative, a PTC thermistor, increases resistance with temperature, which isn’t as straightforward for sensing because you would need to interpret an increasing resistance as temperature. The other two components listed, capacitors and inductors, are not temperature sensors and don’t provide a predictable resistance change with temperature, so they aren’t used for this purpose. Therefore, the type used as a temperature sensor whose resistance decreases with rising temperature is the NTC thermistor.