1. Characteristics of thermistor
Higher sensitivity
The temperature coefficient of resistance of the thermistor is 10 to 100 times greater than that of metal, so it can detect small temperature changes, even up to 10^-6°C. This high sensitivity makes thermistors a great advantage in applications where precise temperature control is required.
Wide operating temperature range
The working temperature range of the thermistor is very wide. Normal temperature devices are suitable for -55℃～315℃, high temperature devices are suitable for temperatures higher than 315℃ (currently up to 2000℃), and low temperature devices are suitable for -273℃～-55℃. This wide temperature range allows thermistors to operate normally in a variety of extreme environments.
small volume
The thermistor's relatively small size allows it to measure the temperature of spaces, cavities, and blood vessels in living organisms that other thermometers cannot measure. This small size also makes thermistors have great potential in miniaturization and integration.
Easy to use
The resistance value of the thermistor can be selected from 0.1 to 100kΩ, which allows users to choose the appropriate resistance value according to actual needs. In addition, the easy processing of the thermistor also allows it to be processed into various complex shapes to adapt to different applications.
Good stability and strong overload capability
The thermistor has good stability and overload capability, and can work stably for a long time in harsh environments. Even in the case of overcurrent or overvoltage, the thermistor can withstand a certain impact without immediate damage.
2. Classification of thermistors
Thermistors are mainly divided into two categories according to different temperature coefficients: positive temperature coefficient thermistors (PTC) and negative temperature coefficient thermistors (NTC).
Positive Temperature Coefficient Thermistor (PTC)
The resistance value of a positive temperature coefficient thermistor increases as the temperature increases. This characteristic makes PTC thermistors widely used in temperature control, overheating protection, etc. When the temperature rises, the resistance value of the PTC thermistor increases, thereby limiting the current passing through it and acting as overheating protection. In addition, PTC thermistors can also be used to make devices such as self-resetting fuses and heaters.
Negative Temperature Coefficient Thermistor (NTC)
The resistance value of a negative temperature coefficient thermistor decreases as the temperature increases. This characteristic makes NTC thermistors widely used in temperature measurement, temperature compensation, etc. Since the resistance value of the NTC thermistor changes significantly with temperature, it can calculate the temperature value by measuring the resistance value. In addition, NTC thermistors can also be used in fields such as surge current limiting and temperature control systems.
In addition to PTC and NTC, there is also a special type of thermistor called critical temperature coefficient thermistor (CTR). CTR thermistor has negative temperature coefficient characteristics, but at a specific temperature point, its resistance value will drop sharply, showing extremely high sensitivity. This characteristic makes CTR thermistors mainly used as thermal control switches and has great application value in situations where precise temperature control is required.
3. Application of thermistor
Because thermistors have the characteristics of high sensitivity, wide operating temperature range, small size, and ease of use, they are widely used in various fields. For example, in electronic circuits, thermistors can be used for temperature detection, temperature control, overheating protection, etc.; in the medical field, thermistors can be used to measure human body temperature, monitor blood vessel temperature in living organisms, etc.; in the industrial field, thermal resistors Sensitive resistors can be used to measure ambient temperature, control heater temperature, etc.
4. Conclusion
As a special resistor, the thermistor has the characteristics of high sensitivity, wide operating temperature range, small size, and easy use. According to different temperature coefficients, it is mainly divided into two categories: positive temperature coefficient thermistor (PTC) and negative temperature coefficient thermistor (NTC), as well as special critical temperature coefficient thermistor (CTR). These different types of thermistors have broad application prospects in various fields. With the continuous development of science and technology, the performance and applications of thermistors will be further improved and expanded.
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