The differences between thermal resistors and thermistors: principles, characteristics and application comparisons
In industrial temperature measurement and temperature monitoring of electronic equipment, thermistors (RTD) and thermistors are two commonly used Temperature Sensors. Although they are all used for temperature measurement, their working principles, material properties and applicable scenarios are quite different. This article will provide a detailed comparison of the differences between thermistors and thermal resistors to assist engineers and purchasers in choosing the appropriate temperature sensor.
1.Overview of Thermal Resistance (RTD)
1.1 Working Principle
The Resistance Temperature Detector (RTD) measures temperature based on the characteristic that the resistance of a metal conductor changes with temperature. Common materials for thermal resistors include platinum (Pt), copper (Cu), and nickel (Ni), among which platinum resistors (PT100, Pt1000) are the most widely used.
1.2 Main Characteristics
Good linearity: The resistance change has an approximately linear relationship with temperature (especially within the range of 0 to 500℃).
High precision:
The measurement accuracy of platinum resistance can reach ±0.1℃ or even higher.
Strong stability:
It is not prone to drift during long-term use and is suitable for industrial environments.
Wide temperature range:
Generally applicable to -200℃ to +850℃ (varies by material).
1.3 Typical Applications
Industrial process control (such as chemical engineering, petroleum, and power)
High-precision temperature measurement in the laboratory
HVAC (Heating, Ventilation and Air Conditioning) system
2.ThermistorConcept
2.1 Working principle
A thermistor is a type of semiconductor resistor whose resistance changes significantly with temperature. It is mainly divided into two categories:
NTC (Negative Temperature Coefficient Thermistor) : As the temperature rises, the resistance decreases.
PTC (Positive Temperature Coefficient Thermistor) : As the temperature rises, the resistance increases (commonly used in overcurrent protection).
2.2 Main Characteristics
High sensitivity:
The resistance value variation of Ntc Thermistors is much greater than that of RTDS, making them suitable for detecting minute temperature changes.
Nonlinear characteristics:
The resistance-temperature relationship changes exponentially and requires calibration or compensation by referring to a table.
Fast response speed:
Small size, low thermal inertia, suitable for rapid temperature measurement.
The temperature range is relatively narrow:
it is usually applicable to -50℃ to +150℃ (some high-temperature types can reach up to 300℃).
2.3 Typical Applications
Consumer electronics (such as temperature monitoring of mobile phones and laptops)
Medical equipment (such as thermometers
Automotive electronics (such as battery temperature monitoring)
3.Thermistors vs. Thermal Resistors: Key Comparison
| Comparison items | Thermal resistor (RTD) | thermistor (NTC/PTC) |
| Materials | Metals (platinum, copper, nickel) | Semiconductor ceramics (manganese, cobalt, nickel oxides) |
| Temperature coefficient | Positive temperature coefficient (PTC) | NTC (negative temperature coefficient), or PTC
|
| Linearity | Good linearity (approximately linear) | Poor (exponential change, compensation required)
|
| Accuracy | High precision (±0.1℃ or higher) | medium (calibration required) |
| Temperature range | -200℃ to +850℃ | -50℃ to +150℃ (Common NTC)
|
| Response speed | Slower (Metals have a large thermal inertia） | Fast (small thermal inertia of semiconductors) |
| Cost | Higher (platinum material is expensive) | medium (calibration required) |
| Typical model | PT100、Pt1000 | (NTC), and PTC thermal protection resistors
|
4.How to choose? Thermal resistor or thermistor?
The situation of choosing a thermal resistor (RTD) :
✅ Requires high precision and long-term stability (e.g. Industrial control)
✅ Wide range (-200 ° C to +850 ° C)
✅ Harsh environment (strong anti-interference ability)
In the case of selecting thermistors (NTC/PTC) :
✅ Requires high sensitivity (such as detection of small temperature changes)
✅ Cost-sensitive applications (such as consumer electronics)
✅ Requires quick response (such as overheat protection for electronic devices)
5.Conclusion
Thermal resistors (RTD) and thermistors each have their own advantages. The choice of which sensor to use depends on the measurement range, accuracy requirements, response speed and cost budget. In the industrial field, platinum resistors (PT100) are usually selected to ensure long-term stability, while in consumer electronics, NTC thermistors are more preferred to reduce costs and improve response speed.