Thermistors — correct physical effect: “A thermistor is a semiconductor device that acts like a piezoresistive resistor.” Decide if this identification of the underlying effect is accurate.

Introduction / Context:Thermistors and piezoresistive elements are both resistive sensors but respond to different stimuli. Mixing these concepts results in selecting the wrong sensor for temperature or force/pressure measurement tasks.

Given Data / Assumptions:

• Thermistor: temperature-sensitive semiconductor resistor (NTC or PTC).
• Piezoresistive element: resistance changes due to mechanical strain (as in strain gauges or MEMS bridges).
• Small-signal measurement context with proper biasing to limit self-heating.

Concept / Approach:A thermistor’s resistance varies primarily with temperature due to semiconductor carrier concentration changes; it does not rely on mechanical stress. Piezoresistive devices, by contrast, change resistance when stressed (pressure, acceleration, strain). Therefore, stating that a thermistor “acts like a piezoresistive resistor” is incorrect; the correct term is “thermoresistive” or “temperature-dependent resistor.”

Step-by-Step Solution:

Verification / Alternative check:NTC thermistors exhibit a negative temperature coefficient; datasheets specify R–T curves and Beta values, not gauge factor. Piezoresistive sensors specify sensitivity to strain/pressure and gauge factors, confirming the different physics.

Why Other Options Are Wrong:

• Correct: False; thermistors are temperature sensors, not strain sensors.
• Valid only for NTC types: Both NTC and PTC respond to temperature, not stress.
• True under mechanical stress: Any incidental stress sensitivity is a secondary effect, not the sensing principle.
• Depends on self-heating: Self-heating alters apparent temperature but does not change the sensor’s fundamental effect.

Common Pitfalls:Confusing “piezoresistive” with “thermoresistive”; overlooking self-heating errors and required bias limits in precision temperature measurements.

Final Answer:Incorrect