30kΩ | GUILCOR SENSORS

30KΩ
Temperature sensors

High-resistance NTC thermistor for sensitive temperature detection in low-power and precision systems.

Maximum precision
+/- 0,20°K

Minimum temperature
-50°C

Maximum temperature
+150°C

Minimum dimensions
2 x 10

Response time

Medium

Drift

Low

Self-warming
Low

Price
Low

What is a 30KΩ sensor ?

The NTC 30 kΩ is a thermistor with a high nominal resistance (30,000 Ω at 25 °C).

It is designed to provide maximum thermal stability and extremely low power consumption, making it ideal for energy-limited devices (IoT sensors, wearable medical devices, battery-operated systems).

Operating principle

The relationship between resistance and temperature follows the exponential law:

R(T) = R₂₅ × e^{β (1/T - 1/T₂₅)}

R₂₅ = 30000 Ω
β ≈ 3900 K
T in kelvins

Technical Specifications

Parameter	Typical value
Nominal resistance (25 °C)	30 000 Ω ±1 %
Constant β	3500–3900 K
Sensitive material	Metallic oxide (Mn, Ni, Co)
Type of case	Epoxy / glass / pearl
Maximum measurement current	0,05 to 0,1 mA
Response time	0,4 to 1 s
Operating temperature	−50 → +150 °C
Lifetime	100,000 thermal cycles

Wiring Configuration

Use as a voltage divider, connected to an analog input of a microcontroller.

 +Vcc
   │
  [Rfixe]
   │────► ADC (µC)
  [NTC 30kΩ]
   │
  GND

Self-warming

Thanks to its very high resistance, self-heating is almost nonexistent (< 0.01 °C).

Ideal for prolonged and precise continuous measurements.

Application areas

🔋 Low-energy IoT sensors and wearable devices

🧠 Precision medical instrumentation

🌡️ Ambient measurement and climate monitoring

⚙️ Long-duration control systems

💧 Measurements in wet or confined environments

Should I choose a 30KΩ sensor ?

Strengths points

🔋 Ultra low power consumption
→ Thanks to its very high resistance, the measurement current is minimal, which extends the lifespan of battery-operated or IoT systems.
🎯 Excellent stability and repeatability
→ Quasi-zero drift over time (< ±0.05 K/year), perfect for long-term measurements and controlled environments.
💧 Anegligible self-heating
→ Thermal dissipation lower than 0.01 °C/mW, ensuring accurate and consistent measurement even during continuous operation.

Weaknesses points

📉 Less suited to rapid temperature changes
→ Its high resistance makes the thermal time constant slightly longer, limiting instantaneous reactivity.
🧮 Strongly nonlinear curve
→ Requires numerical linearization (Steinhart–Hart formula or R/T table) to achieve correct accuracy.
🌡️ High-temperature reduced resolution
→ The variation in resistance decreases significantly beyond 120 °C, reducing measurement sensitivity.

Useful information

Here is some useful information regarding the 30KΩ sensors.

Resistance – Temperature Table (R vs T)

(NTC 30 kΩ at 25 °C, beta constant = 3950 K)

Temperature (°C)	Resistance (Ω)	Temperature (°C)	Resistance (Ω)
−50	748 253	60	8 845
−40	473 703	70	6 643
−30	305 068	80	5 083
−20	201 882	90	3 927
−10	134 522	100	3 057
0	91 381	110	2 366
10	63 044	120	1 851
20	44 210	130	1 457
25	30 000	140	1 144
30	20 583	150	899
40	14 284	160	710
50	10 081	170	564

💡 Between 0 °C and 100 °C, the resistance is divided by about 30 — typical of an NTC with β ≈ 3950 K.

Tolerances and precision classes

Class / Tolerance	Tolerance at 25 °C (R25)	Max error on T° (−40 → +125 °C)	Typical usage
±1 %	±300 Ω	±0,2 K	High-end measurement systems
±2 %	±600 Ω	±0,4 K	Industrial Applications and IoT
±3 %	±900 Ω	±0,6 K	Standard thermal regulation
±5 %	±1 500 Ω	±1 K	Consumer devices

🔹 Glass-encapsulated models are recommended for humid environments and repeated thermal cycles.

Example of application – Steinhart–Hart equation

Complete formul:

1/T = A + B · ln(R) + C · [ln(R)]³

Typical coefficients for NTC 30 kΩ β = 3950 K:

A = 1.4051 × 10⁻³
B = 2.369 × 10⁻⁴
C = 1.019 × 10⁻⁷

🔹 Example 1: Temperature from R

R = 20,583 Ω

ln(20583) = 9,93

1/T = 1,4051e−3 + 2,369e−4 (9,93) + 1,019e−7 (9,93)³ = 3,06e−3

T = 1 / 3,06e−3 = 326,8 K = 53,6 °C

✅ Measured temperature ≈ 54 °C

🔹 Example 2: Resistance from T

T = 80 °C = 353.15 K

R = R₂₅ · e^(β(1/T − 1/T₂₅))

R = 30000 · e^(3950 × (1/353,15 − 1/298,15)) = 5083 Ω

✅ Expected resistance: ≈ 5.08 kΩ

Integration diagram in an electronic system

The NTC 30 kΩ is wired as a voltage divider, ideal for low power circuits and high input impedance ADCs.

🔹 Typical components

Component	Function
NTC 30 kΩ	Temperature sensor
R fixed (30 kΩ)	Reference resistance
Microcontroller (ADC)	Analog Lecture
Capacitor 100 nF	Filtering
Power Supply 3.3 / 5 V	Tension stable

🔹 Functional diagram (ASCII)

  +3.3V / +5V
       │
     [Rfixe]
       │────► ADC (input µC)
     [NTC 30kΩ]
       │
      GND

💡 The measured tension depends on the temperature according to the R/T curve.

The system can be factory calibrated to ensure an absolute accuracy of ±0.2 K.

We integrate any sensor into any probe

Smooth tube

Waterproof

Bayonet

Slot

Atmosphere

Termal block

Stick-in

Thread

Contact

Jacketed

PCBA design

Winding

More than 1,000,000 probes delivered in 2025

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