This page compares Thermocouple vs RTD vs Thermistor and mentions difference between Thermocouple,RTD and Thermistor w.r.t. functions, advantages and. RTD vs. thermistor vs. semiconductor IC. December 29, By Janet Heath Table 1: Comparison of temperature sensing technologies. Adapted from A. Thermistors and RTDs or Resistance Temperature Detectors are two The main difference between the two is the type of material that they are.

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Thermocouples A thermocouple is a temperature-sensing element that converts thermal energy directly into electrical energy. The transfer function of an rtd is not perfectly linear. Due to the difference in temperature changes that both devices can detect, each device has been preferred in certain types of applications.

While keeping the error levels within acceptable values, thermistors can be wired with thousands of feet of cabling while RTDs betwfen only be used slightly over a hundred feet. Difference between rtd, thermocouple and thermistor resistance temperature detectors rtds an rtd sensing element consists of a wire coil or deposited film of pure metal.

The main difference between the two is the type of material that they are made of. Following are the advantages of RTD: The three main technologies you have available from which to thremistor are thermocouples, rtds, and thermistors.

They are used for various applications in batteries, coolants, engines, freezers and incubators for over-temperature shutdown purposes and for monitoring and control of temperatures. The differences are covered in terms of advantages and disadvantages of each of these temperature sensor devices.

Comparison of Thermocouples, RTDs, and Thermistors

No current flows in the second pair, so lead resistance has no effect on accuracy. As cables add resistance to the circuit, using very long wires can alter the reading. In industrial and embedded environments, it is not always practical to measure temperature locally. Thermistors have a much faster response time compared to RTDs. The emf fiketype depends on the difference between the two junctions and is used to determine the temperature.


Thermistors are commonly made with ceramic or polymer materials while RTDs are made of pure metals. Thermistors allow for greater cable lengths compared to RTDs.

Lead wire resistance should be considered, and adopting three and four wire connections can eliminate connection lead resistance effects from measurements.

Thermistors are made out of ceramic or polymer while RTDs are made out of pure metals. The Thermistors are devices whose resistance changes with temperature variation.

Care should also be taken to avoid any strains on the RTD in its application. Electrical temperature measurement is used in a wide thermkstor of industries.

Such devices have improved in performance although the different expansion rates of the substrate and platinum give “strain gauge” effects and stability problems. Hence they are safe compare to all the other types viz.

In the case of a thermocouple, you will use an electrical circuit to measure the difference in voltage between the two wires at the open end and use this to measure the temperature difference between the two ends of the wires. The other differences between the thermistor and rtd are explained below in the comparison chart. It is only used when high accuracy is not required as the resistance of the connecting wires is always included with that of the sensor, thus leading to errors in the signal.

Oakton temp14 thermistor thermometer wboot platinum rtds are suitable for use from 50 to c when longterm stability and repeatability is required. RTDs offer greater stability, accuracy and in some cases repeatability than thermocouples. In terms of performance, thermistors win in almost all aspects. The figure-3 depicts resistance versus temperature relationships for different RTD materials viz.


When choosing a thermocouple, consideration should be given to the insulation, thermocouple type, and probe construction. There is no need to resubmit your comment. Difference between thermocouple, rtd and thermistor this page tjermocouple thermocouple vs rtd vs thermistor and mentions difference between thermocouple, rtd and thermistor w. Advantages of this type of RTD are relatively low cost and fast response.

RTDs have a greater temperature range compared to thermistors.

The figure-1 depicts simple thermocouple construction. Electrical temperature measurement is used in a wide wnd of industries. The temperature gauges must be able to read small changes in temperature. The sensor can measure a wide range of temperatures, from up to c.

Ndifference between rtd and thermocouple and thermistor filetype pdf

Lets replace the ice bath with another isothermal block the new block is at reference temperature t. Thermistors are a type of resistor with an electrical resistance that possesses either a negative or positive temperature coefficient of resistivity. Tcr r c r 0 c r 0 c c in c, or alternately From melting steel to baking cookies, the environment, required measurement resolution and accuracy, and temperature ranges can vary greatly and the type of sensor used to measure these temperatures must be differencd accordingly.

Identifying different types of temperature detectors easa. Response time is also another aspect where thermistors are superior. The best RTDs only have comparable accuracies to common thermistors while lower classes of RTDs are tgermocouple more inaccurate.

The figure-2 depicts temperature vs voltage graphs for different thermocouple types viz. Thermocouple The thermocouple differecne a component used for measurement of temperature.