The coefficient of a thermistor sensor is defined as what?

• A. Maximum resistance value.
• B. Resistance at 0°C.
• C. Temperature at which resistance is zero.
• D. Amount of resistance change per degree Fahrenheit.

Answer: (D)

The coefficient describes how sensitive a thermistor’s resistance is to temperature changes—the rate at which resistance changes as temperature changes. It’s expressed as dR/dT, essentially ohms per degree (per degree Celsius or Fahrenheit). This tells you how much the resistance will shift for a one-degree change in temperature. For an NTC thermistor, this rate is negative (resistance decreases as temperature rises); for a PTC, it’s positive. This concept matters because it determines how strong the sensor’s signal will be for a given temperature change and guides how you bias or linearize the reading. The other statements refer to a single resistance value or to a zero-crossing that isn’t physically meaningful for a thermistor, so they don’t describe how the sensor’s resistance changes with temperature.