How Platinum Resistance Temperature Sensors Use Resistance Variation to Deliver Accurate Temperature Readings

Understanding the Principle Behind Platinum Resistance Temperature Sensors

Platinum resistance temperature sensors, often called RTDs, are widely used for their high accuracy and reliability. But what truly sets them apart is the fundamental relationship between temperature and electrical resistance—a principle that allows these sensors to deliver precise readings over a broad temperature range.

At the core of the platinum RTD is a fine platinum wire or thin film. Platinum, as a metal, has a very predictable resistance change when its temperature changes. This property is known as a positive temperature coefficient (PTC)—as temperature rises, so does the resistance of platinum.

This change is not random; it follows a known and consistent pattern. For instance, in a standard Pt100 sensor, the resistance is exactly 100 ohms at 0°C. As the temperature increases, the resistance increases at a nearly linear rate. This linearity and stability are why platinum is the preferred material for precision temperature sensing.

The actual temperature reading is calculated by passing a small electrical current through the platinum element and measuring the voltage drop across it. Based on Ohm’s law (V = IR), the resistance is determined, and the temperature is inferred using standardized calibration curves (such as those defined by IEC 60751).

Because the resistance changes are so precise and repeatable, platinum resistance temperature sensors are ideal for critical applications—from industrial automation to environmental monitoring—where accurate temperature feedback is essential.

Shenzhen Soway Technology Development Co., Ltd. applies this fundamental principle in all its platinum resistance temperature sensor products, delivering solutions that combine high stability, excellent repeatability, and fast response times. Soway’s platinum RTDs are designed to withstand harsh industrial environments, offering robust construction and reliable long-term performance. With customizable options available, these sensors can be tailored to meet diverse application needs, ensuring precise temperature monitoring and enhanced process control across various industries. Clients trust Soway’s platinum RTDs for their accuracy, durability, and ease of integration into complex measurement systems.