With the appropriate meter, the user can therefore obtain more accurate readings. However, thermistors change resistance by tens of ohm per degree, compared to a smaller number of ohms for RTD sensors. Sensitivity: Both thermistors and RTD react to temperature changes with predictable changes in resistance. However, thermistors with extended temperature range and/or interchangeability features are often more expensive than RTDs. If your application temperature matches the available range, thermistors are probably the best option. If your application involves temperatures above 130☌, your only option is the RTD probe.Ĭost: Thermistors are quite inexpensive compared with RTDs. While some RTDs can reach 600☌, thermistors can only measure up to 130☌. Range: Unlike RTDs, thermistors can only monitor a smaller range of temperature. immunity to electrical noise in the environment.The relationship between temperature and resistance is linear for RTDS, but for NTC thermistors, it is exponential and can be plotted along a curve.īoth RTDs and NTC thermistors require a current or excitation source, and both are suitable for use in applications that require: Whereas in RTDs there is a positive correlation between resistance and temperature (as temperature increases, resistance increases as well), in negative temperature coefficient (NTC) thermistors, the inverse relationship holds (resistance decreases as temperature increases). A thermistor’s system electronics need to match the curve of sensor. However, unlike RTDs which offer established standards, thermistors curves vary depending on the manufacturer. Today’s meters are flexible enough to allow users to set up a broad range of thermistors, and to interchange the probes easily. In recent years, thermistors have become increasingly popular due to improvements in meters and controllers. Thermistors are made up of composite materials, usually metal oxides such as manganese, nickel or copper, along with binding agents and stabilizers. Most RTDs consist of an element made of a pure metal (platinum is most commonly used) and protected within a probe or sheath or embedded into a ceramic substrate. Both thermistors and resistance temperature detectors (RTDs) are types of resistors with resistance values that vary predictably with changes in their temperature.
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