The common functions of NTC thermistor is temperature monitoring, temperature control, temperature protection, temperature compensation, etc. In addition, some applications will also use the dissipation coefficient characteristics of NTC thermistor to measure physical parameters such as air flow, wind speed, and humidity.

NTC thermistor is a sensitive component which resistance value decreases as the temperature rises, using this feature, when the NTC thermistor uses a constant current source as an input source, its volt-ampere characteristics will show that the larger the current first, the greater the voltage (this stage is temporarily called stage I.); When NTC thermistor is used for temperature measurement, the volt-ampere setting must be at this stage, and the smaller the power, the smaller the temperature error; When the current of the constant current source reaches a certain extent, the resistance value of the NTC thermistor will drop significantly due to the influence of heat generated by the power in the circuit, and the volt-ampere characteristic will show that the greater the current, the smaller the voltage (this stage is temporarily called stage II).

Near the midpoint of stage II., at this time, the NTC thermistor will be affected by its own heat generated by power and cause the resistance value to decrease, but its heat dissipation just forms a dynamic balance with the heat generated by the circuit, which will not cause the resistance value to drop further. From another point of view, when the environment temperature changes, its heat dissipation system changes, and the dynamic equilibrium point will also change, which in turn affects the volt-ampere characteristics. Therefore, it can be used to measure the environmental wind speed, gas flow, humidity and other physical parameters that affect the heat dissipation of the thermistor by using the characteristics that the dissipation coefficient of NTC thermistor is affected by the environment.

Specifically, when measuring wind speed, two NTC thermistors of the same specification are generally used as a comparison and used as the bridge arm of the bridge. One of the NTC thermistors as a reference completely isolates the gas to be measured, the other NTC thermistor as a measurement component, when the gas to be measured through the NTC thermistor to change its voltage, at this time the bridge will output different voltages at different wind speeds, according to the voltage output at different wind speeds can fit an equation between voltage and wind speed.

GT series MELF glass encapsulated NTC thermistor produced by EXSENSE Electronics Technology Co., Ltd. can be well adapted to the application of this scenario, each measurement system needs two NTC thermistors of the same specification, and its resistance value needs to be as close as possible, which requires its high precision; NTC thermistors are affected by different wind speeds, which requires them to be highly sensitive; Applications in complex environments such as high temperature and high humidity require NTC thermistors to have strong protection and high reliability.