The function of a basic resistive temperature sensor (RTD) is to measure temperature by utilizing the principle that the electrical resistance of a material changes with temperature. RTDs are commonly made of pure platinum, but they can also be constructed using other materials with a known temperature-resistance relationship.
The basic operation of an RTD relies on the fact that as the temperature increases, the resistance of the sensor also increases in a predictable and repeatable manner. This relationship follows a well-defined and nearly linear curve. The sensitivity of the RTD, expressed as the temperature coefficient of resistance (TCR), indicates the rate at which resistance changes concerning temperature.
Here's how the RTD works:
Temperature Sensing: When the RTD is exposed to a temperature, the temperature-sensing element (usually the platinum wire) undergoes a change in resistance based on the material's TCR.
Electrical Circuit: The RTD is connected to an electrical circuit, typically in a Wheatstone bridge configuration, to measure the change in resistance.
Electrical Output: As the resistance of the RTD changes with temperature, the Wheatstone bridge circuit generates a proportional electrical output signal.
Temperature Measurement: This electrical signal can be measured and converted into temperature readings using appropriate electronics and calibration. By knowing the resistance-temperature relationship of the RTD and comparing it to the measured resistance, the temperature can be accurately determined.
RTDs are widely used in various industrial, scientific, and commercial applications due to their accuracy, stability, and repeatability. They are commonly found in temperature monitoring and control systems, industrial process control, HVAC systems, automotive applications, and scientific research, among others.