Resistance Temperature Detectors or RTDs are used to sense varying temperature ranges and levels of resistance in industrial and commercial applications. An RTD consists of a resistance element and insulated copper wires.

The resistive element is usually made of platinum, nickel, nickel-iron, or copper as these materials have high accuracy, fast response time, and a wide temperature range. The main function of an RTD is to probe increases and decreases in temperature and control them accordingly.

How do RTD Sensors work?

RTDs use a sensor to detect temperature changes. The metal component or RTD resistor is situated in proximity to where the temperature measurement needs to occur. As the electrical current passes through the metal, the resistance element measures the electrical current being passed through it. When the temperature of the metal increases, the RTD increases the electrical resistance, which is measured in Ohms.

The resistance value can be converted into temperature, and the resistance ratio can vary based on the element used for the resistor. The flow of electricity is then decreased, subsequently reducing the temperature.

Types of RTD Sensors

• PT100: A PT100 sensor is typically the most accurate temperature sensor with high levels of stability and repeatability. The Pt100 is a laboratory-grade sensor as it is IEC 60751 compliant.
• PT1000: PT1000 Sensors are also available at similar temperature ranges and tolerances; however, a PT1000 will have a resistance value reading ten times higher than the PT100 for the same temperature. Two, three and four wire sensors are used in RTD sensing circuits.
• RTD: RTD Sensors are configured so the sensor's resistance can be accurately calculated. The lead wire used between the resistance element and measuring element also has its own resistance, so two, three, and four-wire sensors provide a means of compensating errors in temperature and resistance measurement.

RTDs vs Thermocouples

RTDs and thermocouples are both used for measuring temperature, but they work differently. RTDs use the electrical resistance of a material to measure temperature accurately and consistently. Thermocouples, on the other hand, generate a voltage from the temperature difference between two metals. RTD’s offer some advantages over Thermocouples such as a wider temperature measurement, higher accuracy than thermocouples and are easily interchangeable.

Browse our wide range of high-quality RTD sensors for all types of applications. Our RTD Sensors are supplied to you from industry-leading brands, including Electrotherm JUMO Omron Honeywell TE Connectivity and RS PRO