How to Choose a Temperature Sensor?

There are various types of temperature sensors, widely applied in automotive, consumer electronics, household appliances, and more. Among them, the earliest are thermocouples, RTD platinum resistance sensors, and integrated semiconductor temperature sensors, with new types continually emerging with technological advancements.

Common temperature measurement methods vary widely, from industrial temperature transmitters to household electronic thermometers. Different temperature measurement methods are adopted based on specific application scenarios.

Based on the measurement principle, temperature measurement methods can be categorized as follows:

1. Thermocouples: Widest temperature range (-200℃ to 2000℃), but require an external reference junction, making them relatively complex.

2. RTD Platinum Resistance Sensors: High accuracy and wide temperature range, but higher cost and complex peripheral circuits.

3. NTC Thermistors: Lower cost but limited accuracy, with characteristics of large temperature coefficients and nonlinear output.

4. CMOS Temperature Sensors: Also known as IC temperature sensors, available in analog and digital output types. Compared to the other three types, CMOS temperature sensors offer high linearity, low system cost, high integration, simple peripherals, and digital output. However, their temperature measurement range is typically limited to -40℃ to 125℃.

These differences in temperature measurement methods determine their respective application scenarios. Thermocouples and RTDs, with their wide temperature ranges but complexity, are primarily used in industrial applications. NTC thermistors, due to their low cost and ease of use, find widespread applications in automotive systems, household appliances, and IoT devices.

CMOS digital temperature sensors, typically packaged as standard ICs, are commonly used for board-level temperature measurement in electronic products such as hard drives and motherboards. They mainly output signals via I2C interfaces, with some providing analog voltage output. With advancements in CMOS technology, digital temperature sensors are becoming increasingly efficient and cost-effective.