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You don't know NTC thermistor!

Release time:2021-12-25 12:11:41  Views:1073

NTC thermistor is a thermistor with a negative temperature coefficient. Is the use of a single high purity material, close to the theoretical density of the structure of high-performance ceramics. In the realization of miniaturization at the same time, with resistance value, temperature characteristics of small fluctuations, quick response to a variety of temperature changes, can be high sensitivity, high precision detection. Guangdong Southern Hongming provides a variety of shapes, characteristics of small, high reliability products, to meet the application needs of our customers.


Working principle of NTC negative temperature coefficient thermistor


NTC is the abbreviation of Negative Temperature Coefficient, which means Negative Temperature Coefficient. It generally refers to semiconductor materials or components with large Negative Temperature Coefficient. The so-called NTC thermistor is a thermistor with Negative Temperature Coefficient. It is made of metal oxides such as manganese, cobalt, nickel and copper as the main raw materials by ceramic process. These metal oxides have semiconducting properties because they conduct electricity in exactly the same way as semiconducting materials such as germanium and silicon. At low temperatures, the number of carriers in these oxide materials decreases, so the resistance value is higher, and the number of carriers increases, so the resistance value decreases.


NTC negative temperature coefficient thermistor

The Negative Temperature Coefficient (NTC) refers to a thermistor or a material that has a Negative Temperature Coefficient and an exponential decrease in resistance with increasing Temperature. The material is a semiconductor ceramic made of two or more metal oxides such as manganese, copper, silicon, cobalt, iron, nickel and zinc, which is fully mixed, formed and sintered. It can be made into a thermistor with negative temperature coefficient (NTC). The resistivity and material constant vary with the composition ratio, sintering atmosphere, sintering temperature and structure state. Now there are also non-oxide NTC thermistor materials represented by silicon carbide, tin selenide, tantalum nitride, etc.

NTC thermal semi-conductive porcelain is mostly spinel structure or other structures with negative temperature coefficient, the resistance value can be approximately expressed as: RT and RT0 are the resistance value at temperature T and T0 respectively, Bn is the material constant. The resistivity of the ceramic grain itself varies due to temperature changes, which are determined by the semiconductor properties. The rated zero power resistance value is R25, which is the nominal resistance value of the NTC thermistor measured at the reference temperature of 25 ℃. Usually said NTC thermistor how much resistance value, also refers to the value.


NTC negative temperature coefficient thermistor main parameters

Zero power resistance RT (ω)

RT refers to the resistance measured at a specified temperature T using the measured power causing a negligible change in resistance relative to the total measurement error.

The relationship between resistance value and temperature change is as follows:

RT = RN expB(1/T -- 1/TN)

RT: Resistance value of NTC thermistor at temperature T (K).

RN: Resistance value of NTC thermistor at rated temperature TN (K).

T: specified temperature (K).

B: Material constant of NTC thermistor, also known as thermal index.

Exp: The exponent based on the natural number e (e = 2.71828...) .

This relation is an empirical formula and is accurate only in the limited range of the rated temperature TN or the rated resistance value RN, since the material constant B is itself a function of the temperature T.

Rated zero power resistance R25 (ω)

According to the national standard, the rated zero power resistance value is THE resistance value R25 of the NTC thermistor measured at the base temperature of 25 ℃, and the resistance value is the nominal resistance value of the NTC thermistor. Usually said NTC thermistor how much resistance value, also refers to the value. For the common NTC thermistor, the B value range is generally between 2000K and 6000K.


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