Skip to Content

 20KΩ 
 Temperature sensors 

Reliable NTC thermistor for temperature monitoring in electronic devices and automation applications.

 Maximum precision
+/- 0,20°K

 Minimum temperature
-50°C

 Maximum temperature
+150°C

 Minimum dimensions
2 x 10

Response time

Fast

 Drift

Low

 Self-warming
Low

Price
Low

What is a 20KΩ sensor ?Operating principleTechnical SpecificationsWiring ConfigurationSelf-warmingApplication areas

What is a 20KΩ sensor ?

The NTC 20 kΩ is a thermistor with a high nominal resistance (20,000 Ω at 25 °C), ideal for long-term measurement or low-power systems.

Due to its minimal current, it generates very little internal heat, ensuring excellent stability and accuracy over time.

It is a sensor often used in medical devices, embedded electronics, and climate monitoring systems.

Operating principle

The resistance follows the typical exponential law of NTC:

R(T) = R₂₅ × e^{β (1/T - 1/T₂₅)}

  • R₂₅ = 1000 Ω 
  • β ≈ 3500 – 3900 K (depending on manufacturer)
  • T in Kelvins

This resistance variation is measured by a microcontroller through a voltage divider and translated into temperature using the Steinhart–Hart equation.

Technical Specifications

Parameter
 Typical value

Nominal resistance (25 °C)

 20 000 Ω ±1 %
Constant β 3500–3900 K

Sensitive material

Metallic oxide (Mn, Ni, Co)

Type of case Epoxy / glass / ceramic

Maximum measurement current

0,1 mA

Response time

0.3 to 1 s

Operating temperature

−50 → +150 °C

Lifetime

100,000 thermal cycles

Wiring Configuration

The NTC 20 kΩ is used in voltage divider circuits in low-power analog or digital systems.

 +Vcc
   │
  [Rfixe]
   │────► AD (µC)
  [NTC 20kΩ]
   │
  GND

Self-warming

Thanks to its high impedance, self-heating is virtually negligible (<0.015 °C), an advantage for long-term measurements without drift.

Application areas

🧠 Medical and Biomedical Devices

⚙️ Precision Embedded Electronics (IoT, Drones, Autonomous Sensors)

🧱 Slow and Continuous HVAC Systems

🔋 Battery/PCB Thermal Monitoring

🌡️ Scientific Instrumentation and Climate Control


Should I choose a 20KΩ sensor ?

Strengths points

  • 🔋 Ideal for low power consumption systems
         → Its high resistance drastically reduces the measurement current, perfect for IoT, medical, or battery-powered devices.
  • 🎯 Exceptional stability over time
         → Very low drift (< ±0.05 K/year), ensuring reliability over several years without recalibration.
  • 🔥 Almost no self-heating
         → Less than 0.015 °C of error due to dissipation, allows for ultra-stable continuous measurements.
20kΩ sensors

Weaknesses points

  • 📉 Slightly lower responsiveness
    → Its strong resistance implies a slightly longer stabilization time than lower value NTCs.
  • 🧮 Digital conversion necessary
    → The non-linearity requires the use of a lookup table or the Steinhart–Hart formula to calculate the temperature.
  • 🌡️ Reduced accuracy at high temperature
    → As with most NTCs, the resistance drops beyond 100–120 °C.

Useful information

Here is some useful information regarding the 20KΩ sensors.

(NTC 20 kΩ at 25 °C, beta constant = 3950 K)

Temperature (°C) Resistance (Ω) Temperature (°C) Resistance (Ω)
−50 498 836 60 5 866
−40 315 802 70 4 411
−30 203 378 80 3 377
−20 134 164 90 2 604
−10 89 681 100 2 026
0 60 922 110 1 567
10 42 033 120 1 229
20 29 599 130 967
25 20 000 140 760
30 13 726 150 598
40 9 520 160 472
50 6 724 170 373

💡 Between −20 °C and +100 °C, the resistance is divided by approximately 65, following a classic exponential law for β ≈ 3950.

Class / Tolerance
 Tolerance at 25 °C (R25)
 Max error on T° (−40 → +125 °C)
 Typical usage
±1 % ±200 Ω ±0,2 K Applications scientifiques et médicales
±2 % ±400 Ω ±0,4 K Mesures de contrôle industriel
±3 % ±600 Ω ±0,6 K Systèmes embarqués
±5 % ±1 000 Ω ±1 K Dispositifs grand public
🔹 Glass-encapsulated sensors provide the best thermal stability, resistant up to +150 °C.

Complet formul:

1/T = A + B · ln(R) + C · [ln(R)]³

Typical coefficients for NTC 20 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 = 13,726 Ω

ln(13726) = 9,53

1/T = 1,4051e−3 + 2,369e−4 (9,53) + 1,019e−7 (9,53)³ = 3,05e−3

T = 1 / 3,05e−3 = 327,9 K = 54,8 °C

✅ Measured temperature: ≈ 55 °C


🔹 Example 2: Resistance from T

T = 80 °C = 353.15 K

R = R₂₅ · e^(β(1/T − 1/T₂₅))

R = 20000 · e^(3950 × (1/353,15 − 1/298,15)) = 3377 Ω

✅ Expected resistance: ≈ 3.38 kΩ

The NTC 20 kΩ is integrated into a voltage divider, used for analog reading on microcontrollers or low-power instrumentation.

🔹 Typical components

Component
 Function
NTC 20 kΩ Temperature sensor
R fixed (20 kΩ)
 Reference resistance
Microcontroller (ADC)
 Analog Lecture
Capacitor 100 nF
 Noise filtering
Power Supply 3.3 / 5 V
 Tension stable
🔹 Functional diagram (ASCII)
  +3.3V / +5V
       │
     [Rfixe]
       │────► ADC (microcontroller input)
     [NTC 20kΩ]
       │
      GND
💡 Its high resistance allows for stable accuracy with minimal measurement current, perfect for autonomous and sustainable applications.

 We integrate any sensor into any probe 

Smooth tube probe

 Smooth tube 

Waterproof probe

 Waterproof

Bayonet probe

 Bayonet

Slot probe

 Slot

Ambient probe

 Atmosphere

Connection head probe

Termal block

Stick-in probe

Stick-in

Thread probe

Thread

Contact probe

Contact

Jacketed probe

Jacketed

PCBA Design

PCBA design

Winding probe

Winding

More than 1,000,000 probes delivered in 2025

Contact us for a personalized offer

Contact Us

Need a NTC 20KΩ sensor?

Whether you need a few parts for a prototype or several hundred for a production line, we support you at every step.

Submit