Thermistors are pivotal components in temperature sensing, offering precise and reliable measurements across various applications. The term "thermistor" combines "thermal" and "resistor," reflecting their role as temperature-sensitive resistors.


Available in two primary types—Negative Temperature Coefficient (NTC) and Positive Temperature Coefficient (PTC)—thermistors are integral to devices ranging from digital thermometers to automotive sensors and household appliances. Understanding the advantages and disadvantages of thermistors is essential for optimizing their use in different environments and applications.


What is Thermistor?

A thermistor is a type of temperature sensor whose resistance varies with temperature. The term "thermistor" combines "thermal" and "resistor." Typically made from metallic oxides and encased in materials like epoxy or glass, thermistors are classified into two main types:


  • Negative Temperature Coefficient (NTC) Thermistors: Resistance decreases as temperature increases, making them ideal for precise temperature measurements.
  • Positive Temperature Coefficient (PTC) Thermistors: Resistance increases as temperature rises, often used as overcurrent protection devices.


Thermistors offer high precision within a narrow temperature range, generally around ±50ºC of a target temperature. They are commonly used in digital thermometers, automotive temperature sensors, and household appliances. For specialized applications such as laser stabilization and optical devices, thermistors are integrated into the design, like the 10 kΩ thermistor used in laser modules.


Symbol of thermistor

Symbol of thermistor


How does Thermistor Work and the Application

A thermistor operates by changing its electrical resistance in response to temperature changes. In NTC (Negative Temperature Coefficient) thermistors, resistance decreases as temperature rises, while in PTC (Positive Temperature Coefficient) thermistors, resistance increases with temperature. This change in resistance can be measured and converted into a temperature reading. The relationship between resistance and temperature is typically nonlinear and is determined by the thermistor's material composition and design.


Applications of Thermistors:


  • Digital Thermometers: For precise temperature measurement in medical, industrial, and consumer devices.
  • Automotive Sensors: To monitor engine temperature, coolant temperature, and other critical parameters in vehicles.
  • Household Appliances: In devices like ovens, refrigerators, and washing machines for temperature control and safety.
  • Industrial Processes: For monitoring and regulating temperatures in manufacturing and processing equipment.
  • Battery Management Systems: To monitor battery temperature in electric vehicles and portable electronics.
  • HVAC Systems: For temperature sensing and control in heating, ventilation, and air conditioning systems.


Advantages and Disadvantages of Thermistor

Advantages and Disadvantages of Thermistor

In this part we will detail the advantages and disadvantages of  NTC THERMISTORS and PTC THERMISTORS. Let’s move on.

NTC (Negative Temperature Coefficient) Thermistors




High Sensitivity: NTC thermistors exhibit high sensitivity to temperature changes, allowing for precise temperature measurements with a small temperature range.

Wide Temperature Range: They can operate across a broad temperature spectrum, from as low as -55°C to several hundred degrees Celsius, depending on the specific type.

Cost-Effectiveness: NTC thermistors are relatively inexpensive compared to other temperature sensors, making them a cost-effective choice for many applications.

Small Size: Their compact size allows them to be integrated into small electronic devices and systems.

Fast Response Time: They provide quick responses to temperature changes, which is crucial for real-time monitoring and control.




Nonlinear Characteristics: The resistance-temperature relationship is nonlinear, which can complicate the calibration and measurement processes.

Limited Precision: Achieving high precision over a wide temperature range can be challenging due to their nonlinear behavior.

Self-Heating Effect: Internal heat generated by the thermistor during operation can affect its measurement accuracy, especially in low-power circuits.

Stability Issues: NTC thermistors may exhibit variations in resistance and stability over time, requiring periodic calibration or replacement.


PTC (Positive Temperature Coefficient) Thermistors




Self-Limiting Current: PTC thermistors increase in resistance with temperature, which makes them useful as resettable fuses in overcurrent protection applications.

Wide Temperature Range: They can operate over a wide temperature range, from cryogenic temperatures to several hundred degrees Celsius, depending on the type.

Small Size: Their compact form factor allows for integration into small devices and systems.

Fast Response Time: PTC thermistors respond quickly to temperature changes, which is beneficial for real-time temperature monitoring.




Nonlinear Characteristics: The resistance-temperature relationship is nonlinear, which may require additional circuitry for accurate measurement and control.

Limited Precision: PTC thermistors may have limitations in achieving high precision, especially at temperatures far from their base resistance.

Self-Healing Behavior: While their ability to reset after overheating is advantageous, it can lead to inconsistent performance if not properly managed.

Environmental Sensitivity: PTC thermistors may be sensitive to environmental factors such as humidity and pressure, which can impact their performance.



In conclusion, thermistors provide significant benefits in temperature measurement, such as high sensitivity, compact size, and cost-effectiveness. NTC thermistors excel in applications requiring precise temperature readings, while PTC thermistors are useful for overcurrent protection. However, both types have drawbacks, including nonlinear resistance characteristics and potential sensitivity to environmental factors. Recognizing these advantages and disadvantages enables effective selection and application of thermistors, ensuring that they meet the specific needs of various temperature-sensitive systems and processes.


  • How does a PTC thermistor work?

    A PTC thermistor’s resistance increases as the temperature rises. This characteristic is useful for overcurrent protection because the thermistor can act as a resettable fuse by limiting the current when temperatures rise.

  • How do I choose between NTC and PTC thermistors for my application?

    Choose NTC thermistors for applications requiring precise temperature measurements. Opt for PTC thermistors when you need overcurrent protection or resettable fuse functionality. Consider the specific temperature range, response time, and sensitivity required for your application.

  • What is self-heating in thermistors?

    Self-heating occurs when current passes through a thermistor, causing it to generate heat due to its resistance. This can affect measurement accuracy, particularly in low-power applications. Minimizing the current can help reduce self-heating effects.

  • How should thermistors be calibrated?

    Thermistors should be calibrated using a known reference temperature and adjusting the sensor output to match. Calibration should be done periodically to maintain accuracy, especially if the thermistor is used in varying or extreme conditions.

  • What materials are thermistors made from?

    Thermistors are typically made from metallic oxides, which are pressed into shapes like beads, discs, or cylinders. These are then encased in protective materials such as epoxy or glass to ensure durability and stability.

  • Can thermistors be used in extreme temperatures?

    Thermistors are designed for specific temperature ranges. While NTC thermistors can operate from as low as -55°C to several hundred degrees Celsius, and PTC thermistors can handle similar ranges, very high or low temperatures may require specialized thermistor types.

Stay updated with Lisleapex by signing up for the newsletter

Insights submitbox