Resistance thermometer and Advantages, Limitations

The resistance thermometer is also known as resistance temperature detector. By using the sensor the temperature is measured by comparing the resistance of the resistance temperature detector element with temperature. In most of the cases the RTD elements contain a length of fine coiled wire wrapped around the glass core or ceramic. The RTD elements are made up of nickel, typically platinum, copper and pure metal.

Due to the temperature change the material has an expectable change in the resistance. So the change is used to determine the temperature. In many of the industries the thermocouples are slowly replacing due to repeatability and accuracy.


Low drift

High accuracy

Wide operating range

For accuracy applications it is suitable.



Above the 660  temperature it is used in the industry. We can see the replacement of the metal sheet with the glass construction.

Reversing thermometer

In the reversing thermometer is also contains the mercury inside the tube and it records the readings of the given temperature. The thermometer is over turned from upside to down side, to identify the correct temperature where the process needs to be done vice versa. An oceanographer uses this primary device to identify the temperature present in the Ocean. To the capillary tube conventional bulb is attached, so that simultaneously refusal the mercury column breaks off in a uniform manner. Into the smaller bulb the mercury runs downward with the help of small bulb which was attached to the end of the capillary tube, so at such instance there is a possibility to note the temperature readings. A 360° turn in a faraway extended portion of the capillary supports as a device, to prevent advance adding of mercury if the thermometer is get on. The mercury expands fast towards the break-off point. Mainly these types of thermometers are useful to measure the temperature along with the pressure of the subsea. So in this type both unprotected and protected thermometers are used, which is delivered with an auxiliary thermometer. In Nansen bottles those are used. They can read up to 0.01°C, after which few corrections are to be done.


Pyrometer of gases:

Pyrometers of gases dispense difficulties. These are made to overcome by using the soot pyrometer or thin filament pyrometer. In this method small solids are involved and made to contact with the hot gases.

Quartz thermometer

The quartz thermometer is a high accuracy, high precision temperature sensors. This is done by measuring the temperature and by measuring the frequency of the quartz crystal oscillator. The oscillator surrounds a specially cut crystal that outcomes in a lined temperature coefficient of occurrence. Due to high lined we receive high accuracy, done on an important temperature range that contains only comes to one convenient temperature point of reference for calibration, i.e., at the triple point of water.

Rectal thermometer

Rectal thermometer is used to measure the temperature of a person. By using this rectal thermometer we can observe the results to be most accurate. This method is considered as unpleasant method.

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