NTC (Negative Temperature Coefficient) refers to the thermistor phenomenon and material with a negative temperature coefficient and an exponential decrease in resistance as the temperature rises. The material is a semiconductor ceramic made of two or more metal oxides such as manganese, copper, silicon, cobalt, iron, nickel, zinc, etc., which are fully mixed, molded, and sintered, and can be made into a negative temperature coefficient (NTC) thermistor. Its resistivity and material constants vary with the material composition ratio, sintering atmosphere, sintering temperature and structural state. Now there are non-oxide NTC thermistor materials represented by silicon carbide, tin selenide, tantalum nitride, etc.
Features
Power NTC thermistors are mostly used in power supplies to suppress surges. The NTC thermistor for surge suppression is a high-power wafer type thermistor, which is often used in electronic circuits with capacitors, heaters, and motors.
When the circuit power is turned on, the circuit will generate a surge current many times higher than during normal operation. The initial resistance of the NTC thermistor is relatively large, which can suppress the excessive current in the circuit and protect its power supply. Circuit and load.
When the circuit enters the normal working state, the thermistor causes the temperature of the resistance body to rise due to the passing current, and the resistance value drops to a very small value, which will not affect the normal operation of the circuit.