The role of NTC B value.Human motion sensing module

　　The NTC thermistor is a decrease in the rising temperature of the negative temperature coefficient. The B value is the thermal constant of the negative temperature coefficient thermistor, that is, the chip (a semiconductor ceramics) of the thermistor resistor (a semiconductor ceramics) After the high temperature sintering, it forms a material with a certain resistance. One B value.

　　The B value represents the curve of the curve or the sensitive index of temperature. When the unit temperature changes, the resistance value increases the value of the B value. In popular terms, the temperature reduces the resistance. The larger the B value, the steeper the curve, the steeper the curve, the greater the changes in the resistance value, and the relatively sensitive. The smaller the B value, the flatter the curve, the more flat the curve indicates the change of the resistance value. Relatively speaking, the smaller the temperature coefficient of the resistance value. B refers to the change of resistance before the two temperature points. You can use the following formulas to calculate:

　　R1: Zero -power resistance value at temperature T1

　　R2: Zero -power resistance value at temperature T2

　　T1 = 273.15k+(T1 ℃), T2 = 273.15K+(T2 ℃)

　　Their RT relationship curve, we call the curve diagram.

　　The range of B-Value is generally 1800K ~ 5800K

　　Usually two temperature points are 25/50, 25/85, 0/100, 0/50.

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