Glossary of NTC Thermistor
1.Rt --- Zero Power Resistance Value
The resistance value measured at a fixed temperature by adopting sufficiently low power consumption.
2. R25 --- Rated Zero-power Resistance Value
The resistance value measured at 25¡æ by adopting sufficiently low power consumption.
3. B Value
B value is a constant, determined by the ceramic material and represents the slope of the R/T curve,expressed in the following equation
In this formula: |
RT1 is the Zero-power resistance at temperature T1; |
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RT2 is the Zero-power resistance at temperature T2. |
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Unless otherwise specified, B value is determined from measurements made at 25¡æ and 50¡æ It's not a firm constant within the range of working temperature. |
4. Zero-power Resistance-to-Temperature Coefficient
The temperature coefficient of resistance is defined as the relative change in resistance referred to the change in temperature.
In the formula: |
§ÑT-zero power resistance-temperature coefficient at temperature T |
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RT- zero power resistance at temperature T |
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T-temperature (expressed in K) |
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B-B Value |
5. Dissipation factor ¦Ä
The dissipation factor ¦Ä is defined as the ratio of the change in power dissipation and the resultant change in the thermistor¡¯s body temperature.¦Ä=¦¤P/¦¤T. ¦Ä changes in response when the ambient temperature changes, within the operating temperature range.
6. Thermal Time Constant ¦Ó
Thermal Time Constant is the time required by a thermistor to change 63% of the difference between its initial and final temperature. ¦Ó= C/¦Ä
7¡¢Maximum Stable Current
Maximum successive current can be applied in NTC thermistor in the ambient temperature of 25¡æ.
8¡¢Resistance-Temperature Characteristics
The dependence of the zero power resistance on its body temperature.
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