How Do Temperature Sensors Work and What Are They Used For?

Marcin Napierała

September 9, 2025

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5 min czytania

Temperature sensors are the basic elements of the correct functioning of many electronic devices. The precise sensor not only allows temperature monitoring, but also prevents, among other things, excessive heating and damage to electronic systems. What should be the “right temperature sensor”? How do different types of sensors work and what exactly are they used for? We invite you to read!

What is a temperature sensor?

Temperature sensors are an indispensable element in the construction of almost any heating device. These are measuring elements that are responsible for indicating the temperature height, which translates directly, among others, into preventing them from overheating.

What accuracy class characterizes a precision temperature sensor?

The measurement precision, as well as the measuring range of the sensors, varies, among others, depending on the different types of sensors. A precise temperature sensor can indicate the measuring range, for example, with an accuracy of 0.01°C, but the correct measurement accuracy depends primarily on the type of sensor (the error limit in resistive sensors is different than, for example, in thermocouples), and subsequently on the type of connection system between the sensor and the meter or recorder. The efficiency of the temperature sensor should therefore be checked, each time taking into account the legal provisions for the individual models (e.g. the allowed spacing for platinum temperature sensors is precisely described by the standard PN-EN 60751:2009).

Basic types of sensors used for temperature measurement

There are many types of temperature sensors, and each of them is used for completely different purposes. Among the basic examples of temperature sensors we include:

thermoelectric temperature sensors,
resistive temperature sensors,
semiconductor sensors,
integrated sensors,
remote sensors.

Each of the listed categories of temperature sensors has its own subtypes, which are used in various types of devices. Their types, depending on the destination, can be distinguished, among others:

ambient temperature sensors (outdoor temperature sensors)
temperature sensors designed to measure internal temperature

Some temperature level sensors can be accompanied by a humidity sensor and, for example, a pressure sensor and an air quality sensor.

What are temperature sensors used for?

Typically, we categorize temperature sensors primarily according to the way they are built and their destination; taking into account these factors, we list their basic types. Learn elementary examples of temperature sensors and find out where we use them!

Resistive Temperature Sensors

Resistive temperature sensors are the most basic sensors, used mainly for low and medium temperature measurements. In their operation, they use the phenomenon of changing the resistance of the conductor from which they are made. This phenomenon occurs under the influence of a change in temperature. In what devices are resistive temperature sensors used?

central heating furnaces
tempering furnaces
in metallurgical furnaces
in air conditioning and ventilation systems
in engines of means of transport by road, sea and rail
in food industry equipment
in research laboratories

It should be borne in mind that universal temperature sensors do not exist, and the choice of a specific model should be matched to the device in which it is intended to perform its functions. The individual positions of the sensors differ from each other in many elements, e.g. construction, properties, measurement capabilities and purpose.

Example: in metallurgical furnaces, slightly different resistive temperature sensors are usually used than in industrial equipment.

What determines the designation of the temperature sensor type Pt100, Pt500 and Pt1000?

Resistive temperature sensors are divided into their own subtypes: resistive temperature sensor type Pt100, temperature sensor type Pt500 and Pt1000 are their most common examples. As we mentioned, resistive sensors use the phenomenon of changing the resistance of their conductor, which occurs under the influence of a change in the measured temperature.

sensor type Pt100 - a sensor whose resistance (resistance) at 0°C is 100Ω. These sensors can indicate the temperature in the range from -200°C to 800°C (most often, however, their maximum temperature is lower).
Pt500 type sensor - a sensor whose resistance at 0°C is 500Ω (they remain more accurate compared to Pt100 type sensors).
sensor type Pt1000 - a sensor whose resistance at 0°C is 1000Ω (they remain a little more accurate than Pt500 sensors).
Pt100, Pt500 and Pt1000 resistive sensors are used to indicate the temperature of gases, liquids, machine components and installations.

Connection of resistive temperature sensors

Temperature sensors of the Pt100 type can be connected to measuring devices using 2,3 or 4-wire lines, of which (due to cost) the most popular solution is the use of a 2-wire line. However, its choice is associated with the possibility of small measurement deviations, which is why, for example, in industrial temperature measurements, temperature sensors of the Pt100 type are connected by 3-wire lines, which significantly eliminates this error. Measurement deviations are 100% eliminated by the use of 4-wire lines.

note: the use of 3 and 4-wire lines in the connection of temperature sensors requires (it is highly recommended) that the instruments have a measuring input; its presence allows you to fully use the capabilities of the line.

Recommended mounting length of resistive temperature sensors:

in floating water: min. 6-8 diameters of the outer cover of the sensor
in the flowing air: min. 10-15 diameters of the outer cover of the sensor

Thermoelectric sensors (thermocouples)

Thermoelectric sensors are commonly used to make measurements of high and very high temperatures (most often from -270°C to over 1800°C). The main principle of their operation centers around the Seebeck phenomenon; the formation of a potential difference at the point of contact of two different metals, proportional to the difference in their temperatures. Thermocouples remain more resistant to mechanical loads compared to resistance sensors and are used in the following sectors:

in industry (e.g. in the energy, oil and gas, cement and pharmaceutical industries)
in laboratories
in transport
in military equipment
in central heating furnaces
in thermal imaging systems

As in the case of resistive sensors; there are many types of thermoelectric sensors, and according to the provisions of the Polish standard PN-EN 60584-1, the following types of them are distinguished:

Type J thermocouples (-40°C to +750°C)
K-type thermocouples (-200°C to +1200°C)
Type E thermocouples (-200°C to +900°C)
L-type thermocouples (-40°C to +750°C)
Thermocouple type N (+1200°C)
T-type thermocouples (-200°C to +350°C)
Type S thermocouples (platinum, up to 1600°C)
Type R thermocouples (platinum, up to 1600°C)
Type B thermocouples (platinum, up to 1800°C)
Type C thermocouples (up to 2200°C)
Thermocouples type D sensors (up to 2200°C)

Among the most popular thermocouples we include thermocouples of type J, K, E, K, T and N (devoid of precious metals). A less numerous group are high-temperature thermocouples of type S, R and B (platinum); it is highly recommended to use them together with ceramic shields, which in turn cover metal shields. We also distinguish tungsten-rhenium thermocouples type C and type D (used to measure very high temperatures).

Solid State Diodes

Solid state diodes allow temperature measurement in the measurement range from -55°C to +150°C. They are used in all devices where standard temperature control is needed, for example:

in some industries
in ventilation systems

To the basic advantages of the solution, which is the measurement of temperature using a diode, are the relatively low price and small size of the diodes.

Integrated temperature sensors

Integrated sensors are commonly used to measure the temperature inside electrical appliances. Their job is to protect systems from overheating, which can potentially lead to machine damage. Where do we usually use them?

inside electronic devices

Integrated sensors usually perform extremely precise measurements, but their temperature range usually ranges only from -55°C to +150°C. In such sensors, the circuits that process the measurement signal together with the measuring element are located in the same housing, on a semiconductor substrate.

Remote temperature sensors

Remote temperature sensors (so-called transducers) measure temperature at a distance; this type of sensor, contrary to appearances, performs temperature measurement in a much larger range than is the case with integrated sensors. Among some models, this range ranges from -270°C to even +1800°C. Remote temperature sensors are used in the following locations:

inside electrical appliances
in places where measurement conditions are categorised as difficult or very difficult; e.g. in industrial plants (e.g. refineries)

Pressure sensor, temperature sensor, thermostat and air quality sensor - integrations

Temperature sensors They are used in many areas of human life; they are used both in the workplace and in the home. We distinguish many categories of sensors, which in turn can be divided according to different characteristics, e.g. into wireless sensors and internal and external sensors. Temperature sensors can also be standard with other types of sensors.

In which fields are the integration of temperature sensors with other sensors used?

Modern temperature sensors can usually be integrated with other systems, which in turn makes their use almost unlimited. Learn examples of places where we can find integrations of different categories of sensors:

Temperature sensors equipped with air quality sensor or pressure sensor are commonly used in industrial plants where temperature monitoring alone is not sufficient to meet safety standards
The floor temperature sensor can work with the thermostat, which prevents overcooling and excessive overheating of the floor in the house.
Temperature sensors integrated with motion sensors are used in the security industry; e.g. in monitoring systems.

Thanks to technology, the modern range of temperature sensors allows you to find different types of sensors, tailored to individual cases and personalized operating conditions.