Five Types of Temperature Sensors

Temperature sensors are electronic devices that pick up their environment's temperature and convert it into measurable signals. There are many different types of temperature sensors on the market. Each comes with its unique operating principles, considerations, benefits, and downsides, which you have to keep in mind when buying a temperature sensor for a specific application or set of applications.

Read on for some of the most common sensors and their properties.

1. Thermocouples

A thermocouple is a type of temperature sensor formed when the end of a circuit brings together two different metal conductors. Lack of sensing elements makes them more inclusive than resistive temperature devices when it comes to materials used. That is why manufacturers such as Pyrosales Temperature Sensors produce a wider range of thermocouples than most other sensor types in their inventories.

2. Thermistors

Thermistors are resistance thermometers or resistors whose electrical resistance changes with change in temperature. They consist of up to three metallic oxides, placed in a disk, cylindrical device, or bead and enclosed in a glass or epoxy or some other impermeable material. Thermistors are known for their high precision, ease of use, affordability, sturdiness, and relatively predictable responsiveness to temperature changes. Their biggest downside is that they do not perform well in extremely cold or hot environments.

3. Bimetallic strips

Bimetallic strips or bimetal thermostats are made up of two dissimilar metals affixed to form a single strip. These metals are supposed to bend at different rates when exposed to various temperatures, causing curvature. When the environment is cold, the two strips stick together in a straight alignment, allowing current to flow through the thermostat. When heat is applied, a bend occurs, causing the circuit to break and the heating or cooling switch to turn off.

4. IR Pyrometers

IR pyrometers make use of infrared energy to measure temperature changes. They work on the principle that objects will emit infrared energy when subjected to temperatures above absolute zero. Given there is a direct relationship between the infrared energy emitted and its temperature, the pyrometer's sensors measure the infrared energy and display it as a voltage. The three primary factors that have the most sway on the accuracy of IR pyrometers are transmissivity, emissivity, and reflectivity.

5. Resistive Temperature Devices

Resistive temperature devices, or simply RTDs, are a type of sensor fashioned out of conductors such as copper, nickel, or platinum twisted into a coil. They work in a similar fashion as thermistors in that their electrical resistance is dictated by temperature. However, compared to thermistors, RTDs have an extremely linear output, making them highly accurate, though their thermal sensitivity is poor compared to RTDs.

Most RTDs on the market are platinum resistance thermometers, meaning most of the options you will see are expensive owing to the high cost of platinum.

Endnote

If you are looking for a temperature sensor for an industrial application or personal use, you must assess its attributes relative to your specific needs. The above five are some of the most common types of temperature sensors. Take the time to research and understand each of them separately before settling for one.

Back to Homepage

Back to Consumer Goods