Temperature probe sensors are used in laboratory environments to measure the temperature of samples and other objects.
They come in many shapes and sizes and can be used in many different types of applications. In this post, we’ll explain how they work and how you can use them to monitor the temperature in your lab.
What Exactly is a Temperature Probe Sensor?
Temperature sensors for industrial applications are electronic devices that detect the temperature of the environment and transform the data into electronic output to signal variations or enable better control using real-time information. These probe sensors come in different types. Some require direct contact with the item whose temperature they are checking, while others do not require contact with others.
How Does a Probe Sensor Work?
Temperature probes use a sensor, which is typically a thermocouple or a resistance temperature detector, to read the temperature. The thermocouple is made using two dissimilar metals that extend to the end of the device. These metals generate an electrical voltage that is directly proportional to the change in temperature between both ends.
On the other hand, a resistance temperature detector is usually a variable resistor that changes its electrical resistance proportional to the changes in temperature in a way that is precise, linear and repeatable.
Electric current that is generated by the two probe sensors passes across a diode. The resistance on the diode is proportional to the temperature change. Therefore, if it gets very hot or very cold in a short period, the resistance increases or decreases significantly.
Then, the resistance is measured in readable temperature units before being displayed in numeric formats. The units of temperature include Fahrenheit, Celsius and centigrade. It is possible to use the numeric readouts to check the temperature changes over a period.
Types of Temperature Probe sensors
As explained above, there are contact and non-contact temperature probe sensors. Here are the contact ones.
Resistance Temperature Detector (RTD) Probe Sensors
RTD probe sensors are also called resistance thermometers. The RTD elements may be made of different metals, including nickel, copper and platinum. Among the three, platinum is the most accurate and most expensive.
Thermocouple Probe Sensors
These probe sensors also have two wires, like RTD probe sensors, to detect the change in temperature. Its accuracy is slightly lower than that of the RTD probe sensor, but it has a wider range, usually between -200 °C and 1750 °C. It is also cheaper than the RTD version.
NTC Thermistors
A Negative Temperature Coefficient (NTC) thermistor is precise and predictable and changes greatly with the alteration in temperatures. This is because it has a greater resistance to low temperatures. Therefore, a small change is displayed quickly and the change is shown accurately. The large and fast nature of the NTC thermistor means that it requires linearization. Some mathematics is involved in the process.
Thermometers
Thermometers are usually used for checking the body’s and surroundings’ temperatures. There are two types of thermometers; bi-metal and gas-filled and liquid thermometers. The gas-filled and liquid come with a bulb that is filled with either. When it gets heated, the liquid or gas expands at which the attached rod moves a needle to the temperature measured.
On the other hand, the bi-metal thermometer comes with a connected stem and gauge. The tip of the sensor has a spring that is attached to a rod and leads up to the gauge. This needle moves around the gauge, which helps read the temperature.
Semiconductor-based Sensors
A semiconductor-based temperature sensor operates using two combined circuits. The circuits include two similar metals with high sensitivity. These probe sensors provide precise electrical characteristics, including current and voltage, to measure variations. They are the fastest in checking temperature changes but are best used for changes above 5 degrees Celsius.
Non-Contact Temperature Sensors
Most non-contact sensors are infrared sensors from a distance. It measures the thermal radiation emitted by the heat source or object it emits. These probe sensors are used in hazardous environments where the user needs to maintain a safe distance from the source of heat. They can also be used to check body temperatures without contacting the person.
Where are the Temperature Probe Sensors Used?
Temperature probe sensors are used in various applications, including:
- Hazardous locations, such as nuclear and chemical processing plants
- To verify model suppositions to help improve the construction of structures like bridges and buildings
- To measure water temperatures in land reservoirs and boreholes
- In medical applications, to determine the temperatures of patients
Max Page is a visionary and a leading expert in the realm of Android app development, particularly at the intersection of AI and IoT technologies. As the founder and principal author of Agiledroid.com, Max has established himself as a thought leader in harnessing the power of artificial intelligence to revolutionize Android applications.
