There are an abundance of applications where temperature must be monitored and controlled, including personal computers, mobile phones, automobiles, medical equipment, and gaming consoles. Many devices have been developed to match the widely varying technical and economic requirements of these applications, including thermistors, resistance temperature detectors (RTDs), infrared (IR), thermocouples, and more recently, IC temperature sensors

Types of Temperatures sensors:

Contact and Non-Contact


Contact temperature sensors measure their own temperature.
One infers the temperature of the object to which the sensor is in contact by assuming or knowing that the two are in thermal equilibrium, that is,
there is no heat flow between them.

Types of Contact Sensors:



Resistance Temperature Detectors or RTDs

Other Contact Sensors:

Filled System Thermometers
Bimetallic Thermometers
Semiconductor Temperature Sensors


The uses of noncontact temperature sensors are many; the understanding of their use is, in general, relatively poor. Part of that complication is often the need to deal with emissivity, or more precisely with spectral emissivity. In many industrial plants noncontact sensors are not yet standardized to the extent that thermocouples and RTDs are. In spite of this, there are numerous showcase uses of them and they more than pay their way in process plants such as steel, glass, ceramics, forging, heat treating, plastics, baby diapers and semiconductor operations, to name just a few.

Types of Contact Sensors:

Radiation Thermometers

Thermal Imagers


Ratio Thermometers

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