Temperature transducers — linearity comparison Among common temperature sensors, which are generally the most linear over a useful range?

Introduction / Context:
Different temperature sensors trade off linearity, sensitivity, cost, and range. Many industrial systems value linear response for simpler calibration and signal conditioning.

Given Data / Assumptions:

• RTDs (typically platinum) have a near-linear resistance vs. temperature relationship over a wide span.
• Thermistors are highly nonlinear (steep exponential behavior) but very sensitive.
• Thermocouples produce low-level voltages with polynomial compensation needed.
• IC sensors are linear over limited ranges but often reference internal bandgaps and can drift.

Concept / Approach:
Linearity here refers to how closely the sensor's output follows a straight line with temperature, simplifying conversion and reducing error with simple scaling. Platinum RTDs (PT100/PT1000) are industry standards due to excellent linearity and stability.

Step-by-Step Solution:
Compare device physics: RTD metal resistivity vs. T ≈ linear for modest ranges.Thermistors: strong nonlinearity; need linearization.Thermocouples: polynomial relationships and cold-junction compensation required.IC sensors: linear but typically narrower range and device-specific behavior.

Verification / Alternative check:
Standard RTD curves (IEC 60751) show near-linear resistance changes per °C; instrumentation literature favors RTDs for linearity and stability.

Why Other Options Are Wrong:

• Thermistors: nonlinear response.
• Thermocouples: nonlinear voltage output vs. temperature.
• IC sensors: good practicality, but RTDs are the benchmark for linearity over broad ranges.

Common Pitfalls:

• Confusing sensitivity with linearity; thermistors are sensitive but nonlinear.

Final Answer:
Resistance temperature detectors