Last updated on September 13th, 2023 at 04:23 pm

What is a Thermistor?

A Thermistor is a sort of electrical component or resistor that demonstrates a noticeable change in resistance with temperature variations. The terms “thermal” and “resistor” are combined to form the name “thermistor”. Thermistors have been designed to have a highly predictable and nonlinear resistance-temperature characteristic, making them useful in various applications where temperature sensing or control is required.

Because of its compact size, quick responsiveness to changes in temperature, and great sensitivity, thermistors are preferred in many applications. They are especially useful in situations requiring precise temperature measurements or control, such as in temperature-compensated circuits, temperature-sensing devices, or systems requiring temperature-based triggering for specified activities. You can read more about Thermistor here.

What is a Thermocouple?

A Thermocouple is a temperature-sensing instrument used in a variety of industrial, scientific, and commercial applications to measure temperature. The Seebeck Effect, which defines the phenomenon where a voltage is produced when two different metals are linked at their ends and subjected to a temperature gradient, serves as the foundation for how it works. Temperature measurement is possible because this voltage correlates with the difference in temperature between the thermocouple’s two ends. 

Thermocouples are often employed in various sectors such as manufacturing, petrochemical processes, HVAC (heating, ventilation, and air conditioning) systems, and scientific research. They are a well-liked option for temperature measuring in a variety of applications due to their adaptability and dependability. 

Thermistor vs Thermocouple

Let’s examine in further detail how thermistors and thermocouples differ in terms of stability, temperature range, accuracy, and applications:

Stability 

• Thermistors: the stability of thermistors, especially NTC thermistors, is average. They exhibit large resistance fluctuations with temperature and are sensitive to changes in temperature. Age and extended usage may have an impact on their stability.
• Thermocouples: in general, thermocouples provide high stability due to the Seebeck effect, which depends on the electromotive force differential between two different metals, they are less susceptible to ageing or time-related drift.

Temperature Range

• Thermistors:  Thermistors are normally made for a certain range of temperatures. Typical ranges can be as narrow as -50°C to 150°C, depending on the application and thermistor type.
• Thermocouples: they are well known for their ability to operate over a wide temperature range. Depending on the kind and materials  used in the thermocouple, they may monitor temperatures as low as -200°C to far beyond 2,000°C.

Accuracy

• Thermistors: Thermistors have a high degree of precision throughout the range of temperatures they are designed for. They have a very nonlinear resistance-temperature curve that enables accurate monitoring and control over a range of temperatures.
• Thermocouples: The accuracy of thermocouples varies depending on the kind and calibration, although they typically provide acceptable precision. When monitoring temperatures across a large range, they can need more calibration and linearization to attain good accuracy.

Applications

• Thermistors: NTC thermistors are frequently utilized in the following situations:
  
  
  • Temperature compensation in consumer electronics is one application where accuracy within a constrained temperature range is crucial.
  • HVAC system temperature detection and control.
  • Medical equipment that measures body temperature.
  • Industrial tools for regulating and monitoring temperature in certain operations.
    
    
• Thermocouples: Thermocouples are extremely adaptable and are used in many applications that call for measurements throughout a broad temperature range, such as:
  
  
  • High-temperature industrial operations (like glass and steel production).
  • Scientific investigation for data collection and laboratory experiments.
  • Engine temperature monitoring applications in the automotive and aerospace industries.
  • Temperature profiling in the food business for processing and cooking.

In conclusion, thermocouples thrive in applications needing readings across a wide range of temperatures, delivering stability over time and adaptability to harsh circumstances, whereas thermistors are appropriate for applications where precision is needed within a narrow temperature range. The decision between them is based on the application’s limits and particular temperature needs. 

Role of Thermistors and Thermocouples in Industrial Heating

In industrial heating applications, where precise temperature control and monitoring are essential, thermistors and thermocouples play significant roles. Each offers a unique set of benefits and uses in this situation:

Thermistors in Industrial Heating

NTC (Negative Temperature Coefficient) thermistors are often used in industrial heating systems for temperature monitoring and control. They offer precise feedback for sustaining the optimum temperature and are sensitive to temperature fluctuations within a defined range. 

Thermistors can be put in close proximity to heating elements to measure their temperature. The heating elements’ lifespan is increased, energy efficiency is improved, and overheating is prevented. 

The resistance-temperature properties of NTC thermistors may be employed in industrial heating systems for temperature compensation, guaranteeing that the heating process stays constant independent of changes in ambient temperature. 

Thermistors can be used in heating equipment as safety measures. It can sound an alert or turn off the heating system if the temperature rises over a certain threshold, preventing overheating and other risks. 

Thermocouples in Industrial Heating

The capacity of thermocouples to monitor extremely high temperatures makes them ideal for industrial heating operations that entail severe heat, such as furnaces, kilns, and foundries. 

Because of their durability, thermocouples can resist challenging industrial settings including high pressures and corrosive atmospheres. 

Due to their quick reaction times, thermocouples enable quick temperature setpoint modifications in heating systems.

They are adaptable for a variety of industrial heating applications due to the availability of several varieties, each of which is optimised for certain temperature ranges and environmental circumstances.

Multiple thermocouples can be strategically positioned to monitor temperature differences at various places within the system in industrial heating operations that need exact temperature profiling. 

Conclusion 

Finally, it should be noted that thermistors and thermocouples are essential parts of industrial heating applications. Thermistors, especially NTC types, offer precise temperature control and monitoring within predetermined limits, making them the best choice for preserving reliability and safety in operations requiring moderate temperatures. Whereas, thermocouples excel in harsh environments due to their endurance, broad temperature range, and quick reaction times.

Their adaptability extends to hot places like furnaces and kilns. To accomplish exact and thorough temperature management, which ensures effective and secure industrial heating operations, both sensors are frequently combined. The decision is based on the unique temperature requirements and environmental elements of each application.

Many industries use Wattco products to achieve their environmental, economic, and production goals. Contact us to discover which products will best help your application and how we can customize it to meet your needs.