RTD stands for Resistance Temperature Detector. It is a type of temperature sensor that measures temperature by correlating the resistance of the RTD element with temperature changes. RTDs are known for their high accuracy, stability, and repeatability, making them widely used in various industries for temperature measurement and control. There are several types of RTDs based on the material used for the temperature-sensitive element:

1. Platinum RTD (Pt RTD): Platinum RTDs are the most common and widely used type. They utilize a platinum wire or film as the sensing element. Platinum RTDs offer excellent accuracy and stability over a wide temperature range, making them suitable for various applications.

2. Nickel RTD (Ni RTD): Nickel RTDs use a nickel wire or film as the temperature-sensitive element. They are less expensive than platinum RTDs but have a more limited temperature range and lower accuracy.

3. Copper RTD (Cu RTD): Copper RTDs use a copper wire or film as the sensing element. They are less common due to their lower accuracy and limited temperature range compared to platinum RTDs.

Among these types, platinum RTDs are the most commonly used due to their outstanding performance and stability. The most widely adopted standard for platinum RTDs is the PT100, where “PT” stands for Platinum and “100” indicates that the resistance at 0°C is 100 ohms. The resistance of the RTD changes linearly with temperature, allowing for precise temperature measurements over a broad range.

RTDs are employed in various industries, including industrial automation, process control, HVAC systems, automotive, aerospace, and scientific research. Their high accuracy and reliability make them valuable tools for applications where precise temperature monitoring is essential.