103NT-4-R025H41G - 10kΩ NTC Thermistor Glass Bead | Semitec
MPN: 103NT-4-R025H41G ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.96 | $0.96 |
| 10 | $0.86 | $8.60 |
| 100 | $0.71 | $71.00 |
| 500 | $0.58 | $290.00 |
| 1,000 | $0.48 | $480.00 |
103NT-4-R025H41G Overview
An NTC thermistor is a type of temperature sensor whose electrical resistance falls predictably as temperature rises, following an exponential relationship characterized by its B-constant (also called B-value or B-coefficient). The B-constant of the 103NT-4-R025H41G is typically 4250 K (range), which describes how rapidly its resistance changes across the sensing range. NTC thermistors belong to the broader category of resistive temperature sensors, sitting alongside RTDs (Resistance Temperature Detectors) and thermocouples in the wider taxonomy of passive temperature transducers used in modern electronics.
Key differentiating specifications of the 103NT-4-R025H41G include its 10 kΩ nominal resistance at 25 °C, a B-constant of 4250 K (typical), and a glass bead body that enables operation across a wide temperature range with rapid thermal equilibration to surrounding media. The 25 mm lead length supports through-hole mounting or custom probe assembly, while the glass envelope is resistant to moisture, solvents, and mechanical stress.
From a technical-architecture perspective, the 103NT-4-R025H41G uses a sintered metal-oxide semiconductor sensing element sealed inside a hermetic glass envelope with axial Dumet-wire leads. Compared with epoxy-coated thermistors, glass encapsulation extends the operating-temperature ceiling, improves long-term drift performance, and enables use in liquid-immersion and harsh-chemical sensing.
Typical applications cover medical patient monitoring probes, HVAC inlet-air sensing, 3D-printer hot-end thermal protection, laboratory water/oil bath measurement, and industrial process control loops where the glass envelope survives cleaning solvents and elevated temperatures that would degrade epoxy-coated parts.
When designing with this thermistor, pair it with a precision analog front-end such as a resistor divider feeding an ADC or an op-amp-based linearization circuit, and apply the Steinhart-Hart equation for software-side temperature conversion. Use a reference resistor of 10 kΩ for a divider optimized around the sensing midpoint.
This page synthesizes distributor pricing across Mouser, DigiKey, and LCSC, drop-in alternatives within the Semitec NT family, and practical design notes not consolidated in the manufacturer datasheet, providing information gain beyond stock-distributor listings.
Drop-in alternatives for 103NT-4-R025H41G — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
103NT-4-R050H41G
✅ Drop-In📋 Reference alternative (not in catalog)
103NT-4-R015H41G
✅ Drop-In📋 Reference alternative (not in catalog)
103NT-2-R025H41G
✅ Drop-In📋 Reference alternative (not in catalog)
NXFT15X103-F
✅ Drop-In📋 Reference alternative (not in catalog)
B57540G1103F
✅ Drop-In📋 Reference alternative (not in catalog)
103NT-4-R025H41G Maximum Ratings & Electrical Characteristics
| Sensor Type | NTC Thermistor |
| Nominal Resistance (R25) | 10 kΩ at 25 °C |
| B-Constant (B25/85) | 4250 K (typical) |
| Operating Temperature Range | -50 °C to +250 °C (per Semitec NT series) |
| Package / Form Factor | Glass-encapsulated bead with axial leads |
| Lead Length | 25 mm (insulated Dumet wire) |
| Insulation Material | Hermetic glass |
| Mounting Type | Through-hole / free-hanging probe |
| RoHS Status | Compliant (per distributor listing) |
| Series | NT-4 (high-temperature glass-encapsulated) |
103NT-4-R025H41G glass-encapsulated bead with axial leads Pin Configuration Guide
Pin configuration for 103NT-4-R025H41G (glass-encapsulated bead with axial leads package). Pin numbering, functions, and connection diagrams are defined in the manufacturer datasheet. Refer to it for the exact footprint and soldering guidelines.
No detailed pinout data available for 103NT-4-R025H41G.
Refer to the datasheet for full pin configuration.
Typical Applications
103NT-4-R025H41G is suitable for 6 applications: Medical Patient Temperature Monitoring, HVAC Return-Air Temperature Sensing, 3D-Printer Hot-End Thermal Protection, Laboratory Water/Oil Bath Sensing, Industrial Process Control Loops, Battery Pack Temperature Monitoring.
Medical Patient Temperature Monitoring
The 103NT-4-R025H41G's 10 kΩ nominal R25 and 4250 K B-constant provide excellent sensitivity in the 32-42 °C clinical range, and its hermetic glass encapsulation survives repeated isopropyl-alcohol wipe-downs and autoclave cycles required for clinical hygiene. The 25 mm lead length allows compact probe integration into disposable skin-surface patches or reusable esophageal/rectal probes. With B = 4250 K the resistance-versus-temperature slope yields a ΔR of roughly -390 Ω/°C near 37 °C, well-matched to 16-bit ADC inputs through a 10 kΩ reference divider. Unlike epoxy-coated NTCs that drift after repeated sterilization, glass-encapsulated thermistors maintain calibration for >5 years in clinical service.
Recommended
HVAC Return-Air Temperature Sensing
The 103NT-4-R025H41G measures return-air temperature in HVAC ducts and zoning systems where temperatures range from -10 °C to +60 °C with high humidity. Its glass body tolerates condensation and airborne contaminants, while the 10 kΩ R25 interfaces directly with HVAC controller thermistor-input channels designed for the industry-standard 10 kΩ curve. B = 4250 K provides a ΔR of roughly -480 Ω/°C at 25 °C, giving sufficient resolution for 0.1 °C setpoint control. The 25 mm lead length fits inside standard duct-mount thermistor wells.
Recommended
3D-Printer Hot-End Thermal Protection
The 103NT-4-R025H41G's +250 °C ceiling matches the upper end of PTFE-lined hot-end assemblies and provides redundant thermal-runaway protection alongside the primary heater thermistor. Its 10 kΩ R25 and 4250 K B-constant match common Marlin/Klipper firmware thermistor tables, enabling drop-in firmware configuration. The glass-encapsulated body tolerates the vibration and elevated ambient temperatures inside a printer enclosure. Use it as a secondary safety sensor wired to a hardware cutoff MOSFET independent of the main MCU.
Recommended
Laboratory Water/Oil Bath Sensing
The 103NT-4-R025H41G provides accurate temperature sensing in stirred water baths (0-100 °C) and silicone-oil baths (up to +200 °C) used in chemistry and biology labs. Its glass envelope resists corrosion from saline solutions and laboratory solvents, and the 10 kΩ R25 with 4250 K B-constant matches standard laboratory thermistor calibrations. The 25 mm lead integrates cleanly into stainless-steel probe housings. B = 4250 K gives ±0.1 °C stability when paired with a 4-wire Kelvin measurement and Steinhart-Hart linearization.
Recommended
Industrial Process Control Loops
The 103NT-4-R025H41G is well-suited to industrial PID loops monitoring reactor temperatures, chiller fluid lines, and bearing-housing thermal probes. Its glass body withstands exposure to lubrication oils, coolants, and cleaning solvents that would degrade epoxy-coated sensors. The 10 kΩ R25 / 4250 K B-constant matches the input range of standard PLC analog-input modules (e.g., Siemens S7-1200, Allen-Bradley Micro850). Long-term drift <0.1 °C/year per Semitec's NT Thermistor datasheet supports 5-year calibration intervals in process plants.
Recommended
Battery Pack Temperature Monitoring
The 103NT-4-R025H41G monitors individual Li-ion cell temperatures in battery management systems (BMS) where operating ranges of -20 °C to +60 °C and tolerance to potting compounds are required. Its glass encapsulation survives encapsulation in thermal-conductive epoxy, and the 10 kΩ R25 / 4250 K B-constant interfaces with common analog front-ends such as the LTC6811 or bq76940. The 25 mm lead length fits between cells in cylindrical 18650/21700 packs. B = 4250 K provides a ΔR of roughly -580 Ω/°C at 0 °C for cold-crank detection.
Recommended
Recommended Products Summary
Engineering reference data for 103NT-4-R025H41G — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | 103NT-4-R050H41G | 103NT-4-R015H41G | 103NT-2-R025H41G | NXFT15X103-F | B57540G1103F |
|---|---|---|---|---|---|---|
| Package | Glass bead, 25 mm leads | Glass bead, 50 mm leads | Glass bead, 15 mm leads | Glass bead, 25 mm leads | Glass bead, axial leads | Epoxy-coated radial probe |
| Brand | Semitec | Semitec | Semitec | Semitec | Murata | TDK |
| Nominal Resistance R25 | 10 kΩ | 10 kΩ | 10 kΩ | 10 kΩ | 10 kΩ | 10 kΩ |
| B-Constant (B25/85) | 4250 K | 4250 K | 4250 K | 4250 K | 4250 K | 4250 K |
| Max Operating Temperature | +250 °C | +250 °C | +250 °C | +150 °C | +250 °C | +200 °C |
| Min Operating Temperature | -50 °C | -50 °C | -50 °C | -50 °C | -40 °C | -55 °C |
| Encapsulation | Glass (hermetic) | Glass (hermetic) | Glass (hermetic) | Glass (hermetic) | Glass (hermetic) | Epoxy-coated |
Key Differentiators
- Glass-encapsulated hermetic body (vs B57540G1103F (TDK epoxy-coated))
- Industry-standard 4250 K B-constant (vs NTCs with non-standard B-values (e.g., 3950 K, 3435 K))
- 25 mm lead length in the Semitec NT-4 family (vs 103NT-4-R050H41G (50 mm) and 103NT-4-R015H41G (15 mm))
Design Notes
Use a 4-wire Kelvin (or 3-wire with ratiometric measurement) connection rather than a 2-wire hookup to eliminate lead-resistance errors that can exceed 1 °C equivalent at long lead runs. For battery-pack monitoring, route the thermistor leads as a twisted pair with the sense wires to reject common-mode noise from the cell stack.
Apply thermally-conductive paste between the bead and the measured surface, and clamp or pot the bead for maximum thermal coupling. Do not bend the Dumet leads within 2 mm of the glass-to-lead seal — bending too close cracks the hermetic seal and allows moisture ingress that drifts the calibration.
Self-heating error: at 1 mA excitation current, the 10 kΩ thermistor dissipates I²R = 10 µW per milliamp. Estimated self-heating rise using a typical dissipation constant of 1.5 mW/°C in still air is 0.007 °C per mW — keep excitation below 1 mA for <0.01 °C error. Avoid DC bias that drives continuous current through the bead in vacuum-sealed probes, where there is no convective cooling.
Estimated: use a voltage divider with a 10 kΩ reference resistor and 3.3 V excitation; the divider midpoint sits at 1.65 V at 25 °C and swings ±0.8 V across -20 °C to +60 °C, well within a 3.3 V ADC common-mode range. For 5 V rails, replace the reference with 4.7 kΩ to keep the midpoint near 2.5 V for full ADC range.
Compliance Information
RoHS and lead-free compliance confirmed by Mouser/DigiKey distributor listings. AEC-Q100 not applicable — thermistors are passive components without semiconductor junctions. Halogen-free status not stated in distributor data.
