The Different Application Directions of Temperature-Sensitive Elements: NTC and PTC

Temperature-sensitive elements, specifically thermistors, are essential discrete two-terminal devices used in various electronic applications. Based on their resistance changes with temperature, thermistors are classified into two main categories: Negative Temperature Coefficient (NTC) thermistors and Positive Temperature Coefficient (PTC) thermistors. This article explores the different application directions for NTC and PTC temperature-sensitive elements.

NTC Thermistors: Wide-Ranging Applications

NTC thermistors are the most widely used semiconductor temperature-sensitive elements. They are commonly found in temperature sensors and various other electronic products, such as resettable fuses and automatic thermostats. NTC thermistors also play a crucial role in circuit protection.

1. High Sensitivity and Precision: NTC thermistors exhibit a resistance temperature coefficient of 3% to 5% per °C, meaning their resistance significantly decreases as the temperature increases. This high sensitivity allows NTC thermistors to detect even small temperature changes with great precision within the appropriate temperature range.

2. Compact and Cost-Effective: NTC thermistors are small, easy to process, and cost-effective, which greatly expands their application range. One common low-cost temperature detection solution involves connecting an NTC thermistor in series with a pull-up resistor of the same resistance value at room temperature. This design is simple, cost-efficient, and can be processed into various shapes, making it highly popular.

3. Extensive Use in Electronic Systems: Due to their versatility and ease of use, NTC thermistors are widely used in electronic systems, becoming a classic solution for temperature detection. However, because NTC thermistors are nonlinear resistors, they require linearization before temperature measurement and must operate within the appropriate temperature range to ensure accurate results.
 

PTC Thermistors: Reliable and Protective

Linear PTC thermistors are known for their high linearity, precision, and stability, making them essential in temperature detection for complex applications and large equipment. Nonlinear PTC thermistors, on the other hand, are commonly used for overcurrent and overheat protection, rather than temperature detection.

1. Circuit Protection: Nonlinear PTC thermistors have long held a significant position in circuit protection. They are crucial for initial overcurrent and overheat protection but are not suitable for temperature detection.

2. High Linearity for Temperature Detection: PTC thermistors used for temperature detection exhibit high linearity and consistency, with better resistance tolerance compared to NTC thermistors. They do not suffer from heat dissipation issues affecting system power consumption. Due to these advantages, PTC thermistors are more costly and have a narrower application range than NTC thermistors.

3. Specialized Applications: Linear PTC thermistors are commonly used in batteries, security systems, medical devices, research equipment, industrial motors, and aerospace applications. These fields require precise temperature control and stability, which linear PTC thermistors provide. As technology advances and costs decrease, linear PTC thermistors are being adapted for more applications.

In conclusion, both NTC and PTC thermistors are indispensable temperature-sensitive elements, each excelling in different applications. NTC thermistors are favored for their high sensitivity, compact size, and cost-effectiveness, making them ideal for a wide range of uses, including temperature measurement and circuit protection. PTC thermistors, with their high linearity and stability, are crucial for temperature detection in complex and critical applications. Understanding their unique properties and applications ensures optimal performance and reliability in various electronic systems.

Outbound Links

For more detailed information on temperature-sensitive elements, check out the Wikipedia page on Thermistors.

For industry standards and specifications, refer to the International Electrotechnical Commission (IEC) standards.