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AMWEI Thermistor Co -PTC NTC Thermistor, Temperature Sensor Probe, Self-regulating Heater, China Manufacturer

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NTC Thermistor Glossary and Definitio... Selection Reference In... RT Table Application Precaution... Manufacturing Process... PTC Thermistor Structure and Function... Glossary and Definitio... Characteristics... Selection Reference... Application Precaution... Manufacturing Process ...

Inrush Current Limiting Power NTC Thermistor Description Power NTC thermistor can be a cost effective device to limit the amount of inrush current in a switching power supply or other devices when the power is first turned on. Power NTC thermistor limits surge current by functioning as a power resistor which drops from a high cold resistance to a low hot resistance when heated by the current flowing through it. Inrush-current limiters power NTC thermistor protect circuits from undesirably high currents, suppressing high inrush current surges, while its resistance remains negligible low during continuous operation. Thanks to their low resistance in the operating state, Power thermistor have a considerably lower power dissipation than the fixed resistors frequently used for this application. Inrush Current Limiting Power NTC Thermistor Application limiting surge current, suitable for the protection of switch mode power supply, UPS power, various electric heating utensil, energy saving lights, ballast, various power circuit, colored displayer, filament protection, etc. Power thermistor components can also be used for the soft starting of motors, for example in vacuum cleaners with continuous currents of up to 20 A. Inrush Current Limiting Power NTC Thermistor Features: ·Suitable for both AC and DC circuits up to a voltage of 265 V(rms). ·Resin coated leaded thermistor disks. ·Wide range of resistance, current and dimension.

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AMWEI Thermistor Co -PTC NTC Thermistor, Temperature Sensor Probe, Self-regulating Heater, China Manufacturer

Load-temperature characteristics Comparison curve with and without power NTC thermistor application

Typical Application of Inrush Current Limiting Power NTC thermistor for Circuit Protection

Dimensions (mm)

AMWEI Inrush Current Limiting Power NTC Thermistor Data Sheet
Part No. R25 () Max Stable Current
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Approx. Resistance Value at

Dissipation Factor (mW/
oC)

Thermal Time Constant

Dimensions (mm)

AMWEI Thermistor Co -PTC NTC Thermistor, Temperature Sensor Probe, Self-regulating Heater, China Manufacturer

(A)

Maximum Current ()

(s)

D±2 Tmax H

H0

d±1

AMF72-10D5 AMF72-200D5 AMF72-5D7 AMF72-10D7 AMF72-22D7 AMF72-5D9 AMF72-8D9 AMF72-10D9 AMF72-22D9 AMF72-5D11 AMF72-10D11 AMF72-16D11 AMF72-30D11 AMF72-5D13 AMF72-10D13 AMF72-30D13 AMF72-3D15 AMF72-8D15 AMF72-47D15 AMF72-3D20 AMF72-8D20 AMF72-10D20 AMF72-0.7D25 AMF72-1.5D25 AMF72-3D25 AMF72-5D25

5 200 5 10 22 5 8 10 22 5 10 16 30 5 10 30 3 8 47 3 8 10 0.7 1.5 3 5

0.7 0.1 2 1 0.6 3 2 2 1 4 3 2 1.5 5 4 2.5 7 5 3 8 6 6 13 10 9 8

0.771 6.259 0.283 0.616 1.108 0.210 0.400 0.458 0.950 0.156 0.275 0.470 0.667 0.125 0.206 0.517 0.075 0.178 0.680 0.055 0.142 0.162 0.014 0.027 0.044 0.070

9 9 14 9 9 11 11 11 11 13 14 14 15 15 15 16 18 20 21 24 25 24 30 30 32 32

16 16 26 27 27 34 32 32 30 45 47 50 52 68 65 65 76 80 86 88 105 102 120 121 124 125

6.5 6.5 8.5 8.5 8.5 10.5 10.5 10.5 10.5 12.5 12.5 12.5 12.5 14.5 14.5 14.5 16.5 16.5 16.5 21.5 21.5 21.5 26.5 26.5 26.5 26.5

5 5 5 5 5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 6 6 6 6 6 6 7 7 7 8 8 8 8

9.5 9.5

16.5 16.5

5/ 2.5 5/ 2.5 5 5 5 7.5 /5 7.5 /5 7.5 /5 7.5 /5 7.5 /5 7.5 /5 7.5 /5 7.5 /5 7.5 7.5 7.5

11.5 18.5 11.5 18.5 11.5 18.5 13.5 20.5 13.5 20.5 13.5 20.5 13.5 20.5 15.5 22.5 15.5 22.5 15.5 22.5 15.5 22.5 17.5 24.5 17.5 24.5 17.5 24.5

19.5 26.5 10/7.5 19.5 26.5 10/7.5 19.5 26.5 10/7.5 24.5 31.5 10/7.5 24.5 31.5 10/7.5 24.5 31.5 10/7.5 \ \ \ \ \ \ \ \ 10/7.5 10/7.5 10/7.5 10/7.5

Inrush Current Limiting Power NTC thermistor Reliability Data
R25/R25 (typical)

Test

Standard

Test Conditions

Remarks

Storage at upper category Storage in dry heat IEC 60068-2-2 temperature Temperature: 125oC Storage in damp heat, steady state Time: 1000h <10% No visible damage

Temperature of air: 40oC IEC 60068-2-3 Relative humidity of air: 93% Duration: 21 days Lower test temperature: <5% No visible damage

Rapid temperature cycling

IEC 60068-2-14

55oC Upper test temperature: 125oC Number of cycles: 10

<10%

No visible damage

Endurance

\

I=Imax t: 1000h

<10%

No visible damage

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AMWEI Thermistor Co -PTC NTC Thermistor, Temperature Sensor Probe, Self-regulating Heater, China Manufacturer

I=Imax, 1000 cycles OnCyclic endurance \ time=1 min Cooling time=6 min Capacitance=CT Number of cycles: 1000 <10% \

Transient load

\

<5%

No visible damage

Reference information for selecting inrush current limiting power NTC thermistor 1) Maximum operating current > Actual operating current in the power loop 2) Rated zero power resistance at 25C

of which, E: loop voltage, Im: Surge current For conversion power, reversion power, switch power, UPS power, Im=100 times operating current For filament, heater, Im =30 times operating current 3) The larger B value, the smaller residual resistance, the smaller operating temperature rising. 4) Generally, the larger product of time constant and dissipation coefficient, the larger NTC thermal capacity, the more powerful NTC thermistor surge current restraining capacity. Inrush Current Limiting Power NTC Thermistor Application Precautions 1) For inrush current limiting, the NTC thermistor must be connected in series with the load circuit. Several inrush current limiters can also be connected in series for higher damping. Inrush current limiters must not be connected in parallel. 2) In general inrush current limiters require time to get back to cold state, in which they can provide adequate inrush current limiting due to their high resistance. The cooling down time depends on ambient conditions. 3) It should be considered that the surrounding area of NTC Thermistor may become quite hot.

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