How Do PRTs Compare to Thermocouples?

Platinum Resistance Thermometers and thermocouples are the two most common temperature sensors in industry. Choosing between them requires understanding accuracy, stability, temperature range, cost, and application requirements. PRTs use the predictable resistance change of platinum to measure temperature. They offer excellent accuracy, long-term stability, linear output, and repeatability. PRTs perform best in precision applications such as pharmaceuticals, food processing, laboratories, and semiconductor manufacturing. They operate efficiently from cryogenic temperatures up to around 850°C. However, they generally cost more than thermocouples and have slower response times. Thermocouples are made from two joined metal wires and generate a small voltage based on temperature. They are inexpensive, rugged, fast-responding, and can operate at much higher temperatures, often above 1000°C. They are widely used in metallurgy, furnaces, engines, and general industrial applications. However, thermocouples are less accurate, require reference junction compensation, and drift more over time. For critical processes requiring tight control and stability, PRTs are superior. For high-temperature, cost-sensitive, or rugged applications, thermocouples are often more practical. Many modern systems use both: thermocouples for high-temperature monitoring and PRTs for precision control. Understanding the strengths of each allows users to build the most effective temperature measurement system.