LM35 vs. Thermistor

Attribute	LM35	Thermistor
Temperature range	-55°C to 150°C	-50°C to 300°C
Output voltage	10 mV/°C	Varies with resistance
Accuracy	±0.5°C	Depends on type and calibration
Cost	Higher	Lower
Response time	10 ms	Varies

Introduction

LM35 and thermistors are two common types of temperature sensors used in various electronic applications. While both sensors are designed to measure temperature, they have distinct attributes that make them suitable for different scenarios. In this article, we will compare the attributes of LM35 and thermistors to help you understand their differences and choose the right sensor for your project.

Accuracy

One of the key differences between LM35 and thermistors is their accuracy in temperature measurement. LM35 is known for its high accuracy, typically within ±0.5°C. This makes it a reliable choice for applications where precise temperature measurement is crucial, such as in medical devices or industrial control systems. On the other hand, thermistors have a lower accuracy compared to LM35, with typical tolerances ranging from ±1°C to ±5°C. While thermistors may not be as accurate as LM35, they are still suitable for many general-purpose applications.

Response Time

Another important attribute to consider when comparing LM35 and thermistors is their response time. LM35 has a fast response time, typically in the range of milliseconds. This rapid response makes LM35 ideal for applications that require real-time temperature monitoring, such as in HVAC systems or temperature-controlled equipment. In contrast, thermistors have a slower response time compared to LM35, typically in the range of seconds to minutes. This slower response time may not be suitable for applications that require quick temperature changes to be detected.

Temperature Range

LM35 and thermistors also differ in their temperature range capabilities. LM35 is designed to measure temperatures within a specific range, typically from -55°C to 150°C. This limited temperature range makes LM35 suitable for applications where the temperature does not exceed these limits. On the other hand, thermistors have a wider temperature range compared to LM35, with some models capable of measuring temperatures from -50°C to 300°C or even higher. This broader temperature range makes thermistors versatile for applications that involve extreme temperature conditions.

Cost

Cost is another factor to consider when choosing between LM35 and thermistors. LM35 is generally more expensive than thermistors due to its higher accuracy and precision. The cost of LM35 can vary depending on the manufacturer and the specific model, but it is typically higher than that of thermistors. Thermistors, on the other hand, are more cost-effective compared to LM35, making them a budget-friendly option for applications where high accuracy is not a priority. If cost is a significant consideration for your project, thermistors may be the more economical choice.

Calibration

Calibration is an essential aspect of temperature sensors to ensure accurate and reliable temperature measurements. LM35 is factory-calibrated, meaning it does not require additional calibration by the user. This plug-and-play feature makes LM35 convenient and easy to use, especially for beginners or those who do not have the expertise to calibrate sensors. On the other hand, thermistors may require calibration to achieve accurate temperature readings. This calibration process can be time-consuming and may require specialized equipment, making thermistors less user-friendly compared to LM35.

Applications

LM35 and thermistors are used in a wide range of applications due to their temperature sensing capabilities. LM35 is commonly used in precision temperature measurement applications, such as in medical devices, automotive systems, and industrial control systems. Its high accuracy and fast response time make it ideal for applications where precise temperature control is essential. Thermistors, on the other hand, are used in applications where cost-effectiveness and versatility are more important than high accuracy. Thermistors are commonly found in consumer electronics, HVAC systems, and temperature monitoring devices.

Conclusion

In conclusion, LM35 and thermistors are two popular temperature sensors with distinct attributes that make them suitable for different applications. LM35 offers high accuracy, fast response time, and factory calibration, making it ideal for precision temperature measurement applications. Thermistors, on the other hand, are more cost-effective, have a wider temperature range, and may require calibration for accurate readings. When choosing between LM35 and thermistors, consider the specific requirements of your project, such as accuracy, response time, temperature range, cost, and calibration needs, to determine the best sensor for your application.