Temperature is a physical quantity, which defines the hotness or coldness of any object or substance. We can calibrate temperature on several scales and in various units according to our requirements. Kelvin is the international system of units (SI) of temperature, other than Kelvin temperature is measured in Celsius scale and Fahrenheit scale. We can easily convert one temperature unit into another by using simple formulas. For measuring temperature, we use different devices or sensors. Till now, many ways have been developed for measuring temperature. Almost all the modes depend upon measuring some physical property of a working material that differs with temperature. 

Generally used temperature measuring sensors

Thermocouple

Thermocouples, sometimes called “thermo-converters” are an electrical device that is design to measure the heat of an electrically charged surface, such as a conductor, or a non-conductor, insulated wire or a semiconductor material. A thermocouple is simply a detector for measuring physical temperature. This detector comprises two dissimilar metals, usually in the same order, and often connected in the middle, to a thermo-sensitive thermocouple or another thermocouple-capable machine at the other end for getting a reading. Thermocouples have been used for decades and are still used extensively in manufacturing applications in the heating and cooling sectors. Thermocouple sensors are generally made with three to four different electronic components, depending on their use. Thermocouples are placed either inline with the heating source device they monitor or at a distance away from the source so that the results can be extrapolated from ambient temperatures.

RTDs

Resistance temperature detector works similarly as an absolute value thermometer, where they will read the resistance of an electric current, but instead of the current flowing in and moving out, it is measured in resistance. What is nice about resistance temperature alarms is that they can read either the resistance of the current or the absolute value of it. The resistance reading on the device will be the lowest value possible, while the absolute value will be the largest reading possible. Suppose you need to know what the resistance value of a current is. In that case, you can also use a relatively static detector to track the lowest resistance reading and compare it to the most significant value that can be found, and this is because the smallest reading will be close to the maximum available resistance value.

Infrared Sensors

Infrared sensors are non-contacting temperature sensors. For example, suppose you hold up a typical infrared sensor to the front of your desk without contact. In that case, the sensor will tell you the temperature of the desk by its radiation–probably 68°F at average room temperature. The measurement of ice water by a non-contact infrared sensor will gauge somewhat under 0°C in light of dissipation, which marginally brings down the average temperature reading.

Thermometers

Thermometers are known liquid expansion devices also used for temperature measurement. Generally, they come in two main groups: the mercury type and the organic. The distinction between these two is notable because mercury devices have certain limitations regarding how they can be safely transported or shipped. Modern Thermometers uses traditional techniques and new technologies to receive and measure a more accurate and reliable measurement. For instance, IR thermometers now use a new type of sensing called the Spatial Offer Method (SOM). This technology allows a user to determine the precise temperature in a very small space, much smaller than with other types of thermometers. 

Change of state Sensors

Change of state temperature sensors measures a difference in the state of material led to a change in temperature. As in a transition from ice to water and then to steam. Change of state labels indicates temperature measurement in Fahrenheit and Celsius units. Temperature labels are helpful when you need support that the temperature did not exceed a particular level, perhaps for engineering or legal reasons during shipment. Because the change of state devices are non-electrical like the bimetallic strip, they have an advantage in specific applications.

Semiconductor-based temperature sensors 

A semiconductor temperature sensor is usually incorporated into integrated circuits. These sensors utilize two identical diodes with temperature-sensitive voltage-current characteristics for to monitoring temperature changes. They offer a linear response but have the lowest accuracy of the primary sensor types. These temperature sensors also have the most passive responsiveness across the narrowest temperature range.

The Endnote

Many industries using temperature measuring sensors to measure temperature in many different applications. They are all around us, present in both everyday life and more industrial settings. Temperature sensors are vital to everyday life. These crucial pieces of technology measure the amount of heat an object or system is giving off. The measurements given allow us to sense a change in temperature physically. One crucial role of temperature sensors is prevention. Temperature sensors detect when a set high point occurs, which allows time for preventative action.