There are number of methods presented to you that include digital sensor chips, some of which include environmental data like thermocouples and humidity, some of which record temperature, which can be used to measure the extreme temperature. However, the simplest way to carry out this is use a thermistor.
Thermistors can be defined as resistors made of solids and their electrical resistance may differ with temperature. They are constructed from semi-conductor material and take the shape of disc, bead or rod. Their main function is to reveal precise and predictable change in electrical resistance, when related to equivalent change in body temperature. As the resistance of thermistor depends on temperature, it can be easily connected in an electrical circuit for measuring body temperature.
They are sensitive to heat, which means that their level of electrical resistance changes with variation in temperature. Almost all types of resistors exhibit this type of property, but only specialized ones are more sensitive, which makes it easy to measure the temperature precisely.
Owing to the conventional characteristics and long term stability, they are considered to be the most beneficial sensor for various applications apart from temperature measurement and control. There are several companies like Analog Technologies,Inc. that offer thermistors, LCR meter, thermistor assemblies, etc. to satiate different needs of customers.
They are available in two varieties: PTC (positive temperature coefficient) and NTC (Negative temperature coefficient).
The former one is usually used as thermal cut-offs as its resistance increases with the increase in temperature. This is useful property in safety systems. While the latter one is exactly opposite – its resistance decreases with the decrease in temperature.
Thermistors are used as regulators in carrier systems, protective devices, voltage regulators, time delay devices, speech volume limiters, etc. They have higher level of sensitivity, when compared to other types of sensors.
The best thing about thermistors is that they are affordable, flexible and easy to use. They are usually used for temperature readings. This type of resistor is considered highly accurate for temperature readings below freezing point to just above the normal boiling point, but yes they are not suitable for measuring high temperature.
Thermistors can be used for industrial purposes, but the main drawback with them is that they are less able to operate with full efficiency in extreme conditions, when compared to thermocouple.
When there is certain change noticed in electrical resistance of thermistor owing to change in corresponding temperature is apparent whether the thermistor’s body temperature is changed due to radiation/ conduction from surrounding environment or owing to “self-heating” brought by power dissipation within device.
When a thermistor is used in a circuit, the power present within the device doesn’t suffice to cause “self heating”. The body temperature of thermistor follows the environment. It has been observed that thermistors usually are not “self-heated” to be used for temperature control/ measurement/compensation. Instead they are self-heated for use in applications like thermal conductivity measurement, liquid level and air flow detection.
Thus, it can be said that thermistors really prove very beneficial and give true value for investment. To get more information about thermistor and its use, you can refer to various related blogs and articles online that will provide you with enough information on the same.