Axial Leaded Glass Encapsulated Diode DO35 Shape NTC Thermistor Temperature Sensor, 50K Ohm, Beta B(25/50): 3950K, Operating Temperature Range -40C to +250C.

AMWEI Product Code: AMF58-503F3950

Appearance Dimension 

Axial Glass NTC Thermistor Temperature Sensor Dimension

Unit: mm

  • NTC Thermistor chip hermetically sealed in DO35 glass shell.
  • Tinned Dumet wire

Axial Glass NTC Thermistor Application

Axial lead glass encapsulated NTC thermistor used for high temperature measurement, sensing, monitoring, detection and control. Typical application such as  industrial process control, HVAC, oven,  office equipment, etc.

AMWEI Axial Glass Encapsulated NTC Thermistor Electric Characteristics Data

  • Resistance at 25C R25: 50K ohm+/-1%
  • Beta Value B(25/50): 3950K+/-1%
  • Optional R25 resistance tolerance,  ±1%(F), ±2%(G), ±3%(H), or ±5%(J)
  • Dissipation Factor:  δ≥2mW/℃
  • Thermal Time Constant (in still air): 12 seconds max.
  • Rated Power: ≤50mW
  • Insulation resistance: room temperature, 50VDC, 60 Seconds, ≥100MΩ.
  • Operating temperature range: -40 to +250C.

NTC 50K Ohm 3950K Resistance vs. Temperature RT Data

(K Ohm)
(K Ohm )
(K Ohm)
-40C 1592.690 KΩ 80C 6.227 KΩ 200C 0.304 KΩ
-35C 1146.593 KΩ 85C 5.297 KΩ 205C 0.276 KΩ
-30C 836.509 KΩ 90C 4.523 KΩ 210C 0.251 KΩ
-25C 618.146 KΩ 95C 3.876 KΩ 215C 0.229 KΩ
-20C 462.279 KΩ 100C 3.333 KΩ 220C 0.209 KΩ
-15C 349.530 KΩ 105C 2.876 KΩ 225C 0.191 KΩ
-10C 266.928 KΩ 110C 2.489 KΩ 230C 0.175 KΩ
-5C 205.694 KΩ 115C 2.162 KΩ 235C 0.161 KΩ
0C 159.805 KΩ 120C 1.884 KΩ 240C 0.148 KΩ
5C 125.077 KΩ 125C 1.646 KΩ 245C 0.136 KΩ
10C 98.562 KΩ 130C 1.443 KΩ 250C 0.125 KΩ
15C 78.156 KΩ 135C 1.269 KΩ
20C 62.339 KΩ 140C 1.119 KΩ
25C 50.000 KΩ 145C 0.989 KΩ
30C 40.318KΩ 150C 0.877 KΩ
35C 31.354 KΩ 155C 0.781 KΩ
40C 26.624 KΩ 160C 0.698 KΩ
45C 21.800 KΩ 165C 0.624 KΩ
50C 17.941 KΩ 170C 0.560 KΩ
55C 14.870 KΩ 175C 0.503 KΩ
60C 12.384 KΩ 180C 0.453 KΩ
65C 10.362 KΩ 185C 0.409 KΩ
70C 8.708 KΩ 190C 0.369 KΩ
75C 7.349 KΩ 195C 0.335 KΩ

Axial Leaded Glass Encapsulated NTC Thermistor Mechanical Test

Test Standard Test Conditions and methods Requirements
Soldering & Solderability IEC60068-2-20
Test Ta
Temperature: 230±5 ℃,
2-2.5mm away from ceramic body
On: 2±0.5 Seconds.
The terminations shall be evenly tinned
Resistant to soldering heat IEC60068-2-20
Test Tb
Temperature: 260±5℃,
2-2.5mm away from ceramic body
On:10±1 Seconds.
No visible damage,
Lead wire tensile IEC60068-2-21
Test U
Test Ua: Force 10N, On 10 Seconds;
Test Ub: Bending 90C, Force 5N, Twice.
No break off,

Axial Leaded Glass Encapsulated NTC Thermistor Reliability Data

Test Standard Test Conditions ΔR25/R25 (typical) Remarks
Low temperature storage IEC 60068-2-1 Storage at low category
temperature: -30 oC,
Time: 1000 hours
≤3% No visible damage
Storage in dry heat IEC 60068-2-2 Storage at upper category temperature: 200 oC,
Time: 1000 hours
≤3% No visible damage
Storage in damp heat, steady state (Humidity test) IEC 60068-2-3 Temperature: 40oC,
Humidity:90%-95% RH,
Duration:1000 hours
≤3% No visible damage
Temperature cycling IEC 60068-2-14 1. -30C/30 minutes
2. 80C/5 minutes
3. 200C/30 minutes
4. 80C/5 minutes.
Number of cycles: 5 Cycles
≤3% No visible damage

Axial Lead Glass Sealed NTC Thermistor Application Precaution

Minimum lead wire length tailored to shall be ≥8mm.
In lead wire bending, bending point shall be more than 2mm away from glass body part.

Mounting and Handling Recommendations

Excessive forces applied to a sensor may cause serious damage. To avoid this, the following recommendations should be adhered to:

  • No perpendicular forces must be applied to the body
  • During bending, the leads must be supported
  • Bending close to the body must be done very carefully
  • Axial forces to the body can influence the accuracy of the sensor and should be avoided
  • These sensors can be mounted on a minimum pitch of >5 mm

Soldering and Welding

  • Avoid any force on the body or leads during, or just after, soldering.
  • Do not correct the position of an already soldered sensor by pushing, pulling or twisting the body.
  • Prevent fast cooling after soldering.
  • For hand soldering, where mounting is not on a printed-circuit board, the soldering temperature should be <300C the soldering time <3 s and the distance between body and soldering point >1.5 mm.
  • For hand soldering, dip, wave or other bath soldering, mounted on a printed-circuit board, the
  • soldering temperature should be <300C, the soldering time <5 s and the distance between body and soldering point >1.5 mm.
  • The distance between the body and the welding point should be >0.5 mm. Care should be taken to ensure that welding current never passes through the sensor. 

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