# Difference between NTC and PTC Thermistors

**URL:** <https://forumautomation.com/t/difference-between-ntc-and-ptc-thermistors/13781>\
**Category:** Electrical\
**Tags:** basic\
**Created:** [December 17, 2025, 12:27pm UTC](https://forumautomation.com/t/difference-between-ntc-and-ptc-thermistors/13781 "2025-12-17T12:27:45Z")\
**Posts on this page:** 1\
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**Author:** ![Rabert](https://forumautomation.com/user_avatar/forumautomation.com/rabert/32/6784_2.png) [@Rabert](https://forumautomation.com/u/Rabert)\
**Post date:** [December 17, 2025, 12:27pm UTC](https://forumautomation.com/t/difference-between-ntc-and-ptc-thermistors/13781/1 "2025-12-17T12:27:45Z")

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## Difference between NTC and PTC Thermistors

Thermistors are temperature-dependent resistors that are commonly employed in electrical and electronic systems for detecting, controlling and protecting.

Thermistors are categorized into two categories based on their resistance changes with temperature:

- NTC (Negative Temperature Coefficient) Thermistor and
- PTC (Positive Temperature Coefficient) Thermistor

## NTC (Negative Temperature Coefficient) Thermistor

An NTC thermistor is a device whose resistance lowers as temperature increases.

This pattern happens because higher temperatures increase the quantity of charge carriers in semiconductor material lowering resistance.

 ![image](https://cdn.forumautomation.com/original/2X/2/28beb514cb7085ed285f27c65f58d51514c858b3.jpeg)

NTC thermistors are highly sensitive and accurate temperature measurement devices making them ideal for sensing, monitoring & inrush current limiting applications.

## PTC (Positive Temperature Coefficient) Thermistor

A PTC thermistor is a device whose resistance increases as temperature rises particularly after reaching a predetermined threshold temperature.

This rapid increase in resistance limits current flow allowing the thermistor to function as a self-protecting mechanism.

PTC thermistors are mostly employed for thermal and overcurrent safety rather than exact temperature measurements.

## Difference between NTC and PTC Thermistors

## NTC vs PTC Thermistors

| **Parameters** | **NTC Thermistor** | **PTC Thermistor** |
| --- | --- | --- |
| Temperature coefficient | Resistance in an NTC thermistor decreases as temperature increases. | Resistance in a PTC thermistor increases with temperature. |
| Sensitivity | An NTC thermistor is extremely sensitive to minor temperature changes. | A PTC thermistor is less sensitive and reacts mostly around a critical temperature. |
| Resistance - Temperature behaviour | An NTC thermistor exhibits a smooth & continuous nonlinear resistance change. | A PTC thermistor’s resistance increases sharply after reaching a threshold temperature. |
| Accuracy | An NTC thermistor enables precise temperature measurement. | A PTC thermistor is inappropriate for accurate temperature measurements. |
| Primary function | An NTC thermistor is primarily used to measure temperature and control inrush current. | PTC thermistors are primarily utilized for thermal & overcurrent protection. |
| Protection capability | An NTC thermistor does not offer direct protection from overheating. | A PTC thermistor automatically reduces current when it overheats. |
| Typical applications | NTC thermistors are widely utilized in SMPS, battery packs, HVAC systems & sensors. | A PTC thermistor is widely used in motor windings, transformers & resettable fuse circuits. |

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