Temperature sensors are found in many devices that we use today to monitor their temperature. They are used in devices and equipment where the temperature directly or indirectly affects the use or functionality of the device.
You might have seen sometimes your phone displays a warning for overheating. It usually happens when it is placed in a high-temperature area like a kitchen, or it has been on charge for a long time. The warning of overheating comes from the temperature sensor installed by the manufacturer on your phone. Similarly, there are temperature sensors in home appliances like air conditioners and water heaters. Let us know more about the temperature monitoring sensors and their benefits in appliances.
What are temperature sensors?
Temperature sensors are the components in a device or appliance that measure the amount of heat production in an object or system. A temperature monitoring sensor allows the technicians to detect the physical changes in response to the change in temperature or heat generated in a system.
How do the temperature sensors work?
All the temperature sensors consist of a diode that is used to measure the hotness or coolness of an object. The working of a sensor depends on the voltage across the diode. The resistance of the diode changes and is directly proportional to the
change in temperature.
The resistance of the diode is converted into units of temperature that users can read on display. These temperature sensors are used to measure the internal temperature of structures, like buildings, dams, bridges and power plants, etc.
There are many types of temperature sensors available, and they all differ in characteristics. Here are the basic two types of sensors.
Contact type sensors
The contact types temperature sensors are used in devices or appliances where the sensor is required to be physically in contact with the object that needs to be sensed. Also, contact types sensors are used where you need to use conduction to monitor the change in temperature. You can use these types of sensors to detect the change in temperatures of solids, liquids and gases.
These types of sensors make use of radiation of convection to monitor the temperature changes. You can use them to detect liquids and gases that emit radiant energies.
These two types of sensors are further categorized into three groups – Resistive, electronic and electro-mechanical types. Let us explore some more types of temperature sensors.
A thermostat is one of the contact type temperature sensors that consist of a bimetallic strip made of different metals like copper, aluminum, nickel or tungsten. When the temperature of the sensor changes, the metals bend mechanically and the bending is detected by the sensor and converted to an electrical signal that is displayed in the form of temperature units on display.
Thermistors are another type of temperature sensor that is made of ceramic material. They have a negative temperature coefficient which means their resistance is inversely related to their temperature. When the temperature increases, their resistance decreases.
Resistive temperature detectors
These are the sensors made of highly pure metals like copper, nickel, or platinum wound in the form of a coil. The resistance of resistive temperature detectors changes similar to that of thermistors.
Thermocouples are widely popular due to their accuracy, sensitivity and simplicity of use. A thermocouple has two junctions made of different metals weld together. One of these junctions is kept cold at a specific temperature, while the other one is used to measure the temperature of the device in which it is fitted.
NTC means negative temperature coefficient and an NTC thermistor is highly sensitive to changes in temperature. They offer high resistance to even slight temperature changes. The resistance also drops quickly with the decline in the temperature of the device in which the NTC thermistor is used.
Due to the high sensitivity of NTC thermistors to temperature change, it delivers accurate results and highly useful for multiple applications in industries. The high sensitivity to temperature is due to its exponential working principle and requires linearization. They are used for the temperature range of -50-to-250-degree Celsius.
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These were some important points about temperature monitors with sensors. However, there are multiple types of temperature monitors, as mentioned in this post. Manufacturers use the right type of monitors depending upon the device and the environment where the device is meant to be used by the end users. Knowing the requirements of end users enables manufacturers to create the right products suitable for the customers that deliver maximum value to them.