3kΩ | GUILCOR SENSORS

3KΩ
Temperature sensors

Versatile NTC thermistor designed for accurate temperature monitoring in industrial and consumer electronics.

Maximum precision
+/- 0,10°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 3KΩ sensor ?

The NTC 3 kΩ is a thermistor with a nominal resistance of 3,000 Ω at 25 °C.

It offers greater stability and reduced self-heating compared to the 1 kΩ and 2 kΩ versions, while maintaining very good sensitivity in the 0–100 °C range.

It is an excellent compromise between accuracy, local linearity, and robustness.

Operating principle

As with all NTCs, the resistance decreases exponentially with temperature:

R(T) = R₂₅ · e^(β(1/T − 1/T₂₅))

R₂₅ = 3 000 Ω
β ≈ 3950 K
T exprimée en kelvins

The signal is then linearized via software (β formula or Steinhart–Hart equation).

Technical specifications

Parameter	Typical value
Nominal resistance (25 °C)	3000 Ω ±1 %
Constant β	3500–3950 K
Sensitive material	Metallic oxide (Mn, Ni, Co)
Type of case	Epoxy / glass / pearl
Maximum measurement current.	1 mA (to limit self-heating)
Response time	0.3 to 1 s
Operating temperature	−50 → +150 °C
Lifetime	100,000 thermal cycles

Wiring Configuration

Always in 2 wires via a voltage divider bridge, or integrated into an analog measurement module.

 +Vcc
   │
  [Rfixe]
   │────► ADC
  [NTC 3kΩ]
   │
  GND

Self-warming

Less than 0.03 °C for a measurement current of 0.3 mA — excellent for precision applications.

Application areas

🧭 Ambient temperature measurement in control electronics

⚙️ Regulation and thermal compensation in analog circuits

💧 Submersible sensors for liquids and gases

🧱 Air conditioning systems, HVAC, OEM probes

🧠 Medical and metrological equipment

Should I choose a 3KΩ sensor ?

Strengths points

🎯 Very good thermal stability
→ The 3 kΩ offers low drift and minimal self-heating, ensuring excellent measurement repeatability over the long term.
⚙️ Ideal compromise sensitivity / consumption→ It maintains good sensitivity around 25 °C while reducing the current flowing through, perfect for precise but low-power systems
💶 Economic and sturdy
→ Its simple construction and low cost make it a reliable and durable choice for industrial and HVAC applications.

Weaknesses points

📉 Non-linear response
→ Like all NTCs, the voltage-temperature conversion requires software processing, which complicates calculations without a microcontroller.
🌡️ Decreasing sensitivity at high temperature
→ The variation in resistance becomes less pronounced beyond 100 °C, which reduces accuracy in the higher ranges.
🔋 Measurement current dependence
→ A current that is too strong can distort the values: the design of the bridge must be carefully calibrated.

Useful information

Here is some useful information regarding the 3KΩ sensors.

Resistance Table – Temperature (R vs T)

(NTC 3 kΩ at 25 °C, beta constant = 3950 K)

Temperature (°C)	Resistance (Ω)	Temperature (°C)	Resistance (Ω)
−50	74 826	60	879
−40	47 410	70	661
−30	30 507	80	506
−20	20 125	90	390
−10	13 451	100	305
0	9 136	110	241
10	6 283	120	192
20	4 421	130	154
25	3 000	140	124
30	2 058	150	100
40	1 428	160	81
50	1 008	170	66

💡 Entre 0 °C et 50 °C, la résistance est divisée par environ 9 — caractéristique typique d’une NTC à β ≈ 3950.

Tolerances and precision classes

Class / Tolerance	Tolerance at 25 °C (R25)	Max error on T° (−40 → +125 °C)	Typical usage
±1 %	±30 Ω	±0,2 K	Laboratory applications and calibrated sensors
±2 %	±60 Ω	±0,4 K	HVAC and industrial systems
±3 %	±90 Ω	±0,6 K	Common electronic devices
±5 %	±150 Ω	±1 K	Public or security applications

🔹 The 3 kΩ NTCs coated with glass or ceramic ensure excellent thermal stability up to 150 °C.

Example of Application – Steinhart–Hart Equation

Complete equation:

1/T = A + B · ln(R) + C · [ln(R)]³

Typical coefficients for a 3 kΩ NTC, β = 3950 K:

A = 1,4051 × 10⁻³
B = 2,369 × 10⁻⁴
C = 1,019 × 10⁻⁷

🔹 Example 1: temperature from R

R = 2058 Ω

ln(2058) = 7,629

1/T = 1,4051e−3 + 2,369e−4 (7,629) + 1,019e−7 (7,629)³ = 3,06e−3

T = 1 / 3,06e−3 = 326,8 K = 53,6 °C

✅ Temperature ≈ 54 °C

🔹 Example 2: resistance from T

T = 80 °C = 353.15 K

R = R₂₅ · e^(β(1/T − 1/T₂₅))

R = 3000 · e^(3950 × (1/353,15 − 1/298,15)) = 506 Ω

✅ Expected resistance ≈ 506 Ω

Schéma d’intégration dans un système électronique

🔹 Typical components

Component	Function
NTC 3 kΩ	Temperature sensor
Fixed resistor (3 kΩ)	Bridge reference
Microcontroller	Lecture ADC
Power Supply 3.3 / 5 V	Tension stable
100 nF capacitor	Noise filtering

🔹 Functional diagram (ASCII)

  +3.3V / +5V
       │
     [Rfixe]
       │────► ADC (microcontroller input)
     [NTC 3kΩ]
       │
      GND

💡 A two-point calibration (0 °C and 100 °C) improves the effective accuracy to ±0.1 K.

We integrate any sensor into any probe

Smooth tube

Waterproof

Bayonet

Slot

Atmosphere

Termal block

Stick-in

Thread

Contact

Jacketed

PCBA design

Winding

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