Radial Leaded Glass Encapsulated Bead NTC Thermistor 50K Ohm Beta B(25/50) 3950K, Temperature Measurement -40C to +300C

AMWEI Part No. AMF58B-503F3950

Radial Glass Bead NTC Shape and Dimension

Radial Glass Bead NTC Thermistor

Radial Glass Bead NTC Thermistor

  • Glass body diameter D: 1.3±0.2 mm
  • Glass body Length L1: 2.8 mm Max
  • Dumet Lead Wire (copper-clad FeNi) length L2: 65±5 mm
  • Dumet Lead Wire  Diameter Φd: 0.2 ±0.05 mm:
D L1 L2 Φd±0.05
1.3±0.2 mm 2.8 mm Max 65±5 mm 0.2 mm

Radial Glass Bead NTC 50K Ohm 3950K Application

For high temperature measurement upto 300C. Typical application in industrial process control, motors, heating and air conditioning (HVAC) , medical industry, 3D printing, food processing, etc.

Radial Glass Bead 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: 0.5 mw/℃ min.
  • Thermal Time Constant (in still air): 6.5 seconds max.
  • Insulation resistance: room temperature, 50VDC, 60 Seconds, 10 MΩ min.
  • Operating temperature range: -40 to +300C.

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

(K Ohm)
(K Ohm)
(K Ohm)
-40C 1554.810KΩ 80C 6.213 KΩ 200C 0.298 KΩ
-35C 1127.023 KΩ 85C 5.274KΩ 205C 0.272 KΩ
-30C 833.379 KΩ 90C 4.493 KΩ 210C 0.248 KΩ
-25C 623.157 KΩ 95C 3.841 KΩ 215C 0.227 KΩ
-20C 469.250 KΩ 100C 3.296 KΩ 220C 0.208 KΩ
-15C 355.359 KΩ 105C 2.838 KΩ 225C 0.191 KΩ
-10C 270.668 KΩ 110C 2.453 KΩ 230C 0.176 KΩ
-5C 207.518 KΩ 115C 2.128 KΩ 235C 0.162 KΩ
0C 160.297 KΩ 120C 1.853 KΩ 240C 0.150 KΩ
5C 124.848 KΩ 125C 1.620 KΩ 245C 0.139 KΩ
10C 98.085 KΩ 130C 1.422 KΩ 250C 0.129 KΩ
15C 77.731 KΩ 135C 1.253 KΩ 255C 0.119 KΩ
20C 62.111 KΩ 140C 1.108 KΩ 260C 0.111 KΩ
25C 50.000 KΩ 145C 0.984 KΩ 265C 0.103 KΩ
30C 40.501 KΩ 150C 0.878 KΩ 270C 0.096 KΩ
35C 32.962 KΩ 155C 0.778 KΩ 275C 0.089 KΩ
40C 26.905 KΩ 160C 0.692 KΩ 280C 0.083 KΩ
45C 21.983 KΩ 165C 0.617 KΩ 285C 0.078 KΩ
50C 17.941 KΩ 170C 0.552 KΩ 290C 0.073 KΩ
55C 14.883 KΩ 175C 0.495 KΩ 295C 0.068 KΩ
60C 12.401 KΩ 180C 0.445 KΩ 300C 0.064 KΩ
65C 10.375 KΩ 185C 0.401 KΩ
70C 8.713 KΩ 190C 0.363 KΩ
75C 7.344 KΩ 195C 0.329 KΩ

Radial Glass Bead 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,

Radial Glass Bead NTC Thermistor Reliability Data

Test Standard Test Conditions ΔR25/R25 (typical) Remarks
Low temperature storage IEC 60068-2-1 Storage at low category temperature: -40C, Time: 1000 hours ≤3% No visible damage
Storage in dry heat IEC 60068-2-2 Storage at upper category temperature: 250C, Time: 1000 hours ≤3% No visible damage
Storage in damp heat, steady state (Humidity test) IEC 60068-2-3 Temperature: 40C,
Humidity:90%-95% RH,
Duration: 1000 hours
≤3% No visible damage
Temperature cycling IEC 60068-2-14 1. -30C/30 minutes
2. 80C/5minutes
3. 250C/30 minutes
4. 80C/5minutes.
Number of cycles: 5 Cycles
≤3% No visible damage

Contact of NTC thermistors with any liquids and solvents shall be prevented. It must be ensured that no water enters the NTC thermistors (e.g. through plug terminals).
Avoid dewing and condensation unless thermistor is specified for these conditions.


Standard package is loose bulk plastic bag package.

Note: Other Resistance Part and More information can be founded in AMWEI Radial Leaded Glass Encapsulated NTC Thermistor Temperature Sensor Temperature Sensor Page.

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