How to use power type thermistor

Power type thermistor is NTC negative temperature coefficient thermistor, its working principle: NTC is the abbreviation of Negative Temperature Coefficient, which means negative temperature coefficient, generally refers to semiconductor material or component with large negative temperature coefficient, so-called NTC heat The varistor is a negative temperature coefficient thermistor. It is made of a metal oxide such as manganese, cobalt, nickel and copper, and is made by a ceramic process.

The NTC thermistor can be used on the AC line or at the DC output of the bridge rectifier to suppress the surge current. The working principle is: when the power switch is turned on, the NTC thermistor is in a cold state, and the resistance value is large, which can suppress the surge pulse current flowing through the resistor body, and under the dual action of the surge pulse current and the working current, the NTC The temperature of the thermistor will rise, and since it has a negative temperature coefficient characteristic, the temperature rises and the resistance value drops sharply.

Under the steady-state load current, the resistance value will be very small, only about 1/20~1/50 in the cold state, the limiting effect on the current will be small, the power consumed is small, and will not affect the whole. The efficiency of the power supply. Therefore, the constant electronic power type NTC thermistor is a simple measure for suppressing the starting surge current and protecting the electronic equipment from damage when used in the same power source. MF72, MF73, MF74 series NTC thermistors are used to suppress surges.