The NTC resistance value decreases with increasing temperature. Using this feature can be made into temperature measurement, temperature compensation and temperature control components, and can also be made into power-type components to suppress the surge current of the circuit. This is because NTC thermistors have a rated zero power resistance value. When it is connected in series in the power circuit, it can effectively suppress the startup surge current. And after the effect of suppressing the inrush current is completed, the resistance of the NTC thermistor is reduced to a very small extent by the continuous effect of the current)

[Nominal resistance]
The nominal resistance is the resistance value of the NTC thermistor design, which is often marked on the surface of the thermistor. The nominal resistance value refers to the zero power resistance value when the reference temperature is 25 ° C, so it is also called the resistance value R25.

【rated power】
Rated power refers to the allowable power dissipation of the thermistor under long-term continuous load under atmospheric conditions with an ambient temperature of 25 ° C, relative humidity of 45% to 80%, and atmospheric pressure of 0.87 to 1.07Pa.
[B value range]
The B value range (K) is the thermistor index of the negative temperature coefficient thermistor, which reflects the resistance change between two temperatures. It is defined as the ratio of the difference between the natural logarithm of the zero power resistance value at two temperatures to the difference between the reciprocals of this temperature. The B value can be calculated using the following formula, which is
In the formula, R1 and R2 are resistance values (Ω) at the absolute temperatures T1 and T2, respectively.

A: Size chart

II: Product Features:
 
1: MF5A series of products for the lead with an epoxy coating type
2: Wide range of resistance: 1KΩ ~ 500KΩ
3: Resistance and B value of high accuracy
4: high precision
5: small, reflecting the speed
6: is stable for a long time, consistency
7: Operating temperature range: -40 ~ 125 ℃
Product Applications:Air-conditioning equipment, heating equipment, medical equipment, temperature control instrumentation, electronic gifts, electronic hygrometer, car thermometer, electronic calendar, rechargeable battery pack and charger.
MF 5A 103 F 3950
① ② ③ ④ ⑤
①MF ¬-- negative temperature coefficient (NTC) thermistor Code.
②5A-- epoxy encapsulated thermistor.
③103 - thermistor nominal resistance, indicating that the nominal resistance of the resistance: 10 × 103 (Ω).
Error ④F-- resistance value (accuracy) is: F = ± 1%, G = ± 2%, H = ± 3%, J = ± 5%
⑤3950-- thermal resistance index (material factor) B is: 395 × 10 (K)
Five: MF5A Series Model Specification
Note:
     1) Because MF5A series smaller, small joints, lead the ends can not withstand excessive strain.
     2) When soldering, please at least 5mm welding, soldering lead time should be as short as possible from the roots.

Model	Rated resistance（R25）		B Value	work Temperature	Dissipation factor（mW/℃）	Thermal time constant（S）
	Resistance （KΩ）	Tolerance （± %）	Nominal value （K）
MF5A-102-3950	1	±1% ±2% ±3% ±5%	3950	-40℃ ~ +125℃	≥3.0 Still air	≤7 Still air
MF5A-202-3435	2		3435
MF5A-2.252-3935	2.252		3935
MF5A-472-3950	4.7		3950
MF5A-502-3470	5		3470
MF5A-502-3950	5		3950
MF5A-682-3977	6.8		3977
MF5A-682-4200	6.8		4200
MF5A-103-3435	10		3435
MF5A-103-3470	10		3470
MF5A-103-3600	10		3600
MF5A-103-3950	10		3950
MF5A-103-3977	10		3977
MF5A-103-4100	10		4100
MF5A-203-3950	20		3950
MF5A-233-3950	23		3950
MF5A-303-3950	30		3950
MF5A-40.27-3950	40.27		3950
MF5A-473-3950	47		3950
MF5A-49.12-3950	49.12		3950
MF5A-503-3950	50		3950
MF5A-503-3990	50		3990
MF5A-503-4050	50		4050
MF5A-104-3950	100		3950
MF5A-104-3990	100		3990
MF5A-104-4200	100		4200
MF5A-154-4400	150		4400