temperaturkontrollteknik, Termistorteknik

What is an NTC Temperature Sensor?

What is an NTC temperature sensor?

NTC (negativ temperaturkoefficient) temperature sensor is a temperature measuring element that uses the exponential decrease in the resistance of a thermistor as the temperature rises. Its core is a ceramic semiconductor made by sintering metal oxides (such as manganese, cobalt, och nickel), and the temperature is inferred by measuring the change in resistance. The following are its core technical characteristics, applikationer, and selection points:

What is an NTC temperature sensor?

What is an NTC temperature sensor?

Selection and application of NTC temperature sensors

Selection and application of NTC temperature sensors

Functions of NTC temperature sensors

Functions of NTC temperature sensors

jag. Core characteristics‌
‌Working principle‌
När temperaturen stiger, the carrier concentration of the semiconductor material surges and the resistance value decreases (negative temperature coefficient characteristics).

The resistance-temperature relationship conforms to the ‌Steinhart-Hart equation‌: R=, where the B value (material constant) determines the sensitivity.

Hur det fungerar:
NTC thermistors utilize the negative temperature coefficient principle, where the resistance of the material decreases as the temperature increases. This relationship is usually non-linear.

‌Key parameters‌
‌Nominal resistance (R25): reference resistance at 25°C (such as 5kΩ, 10, 100).
‌B value‌: reflects temperature sensitivity (common 3435K, 3950K, etc.), the higher the value, the stronger the sensitivity.
‌Thermal time constant‌: response speed indicator (milliseconds to seconds).
‌Accuracy‌: industrial grade can reach ±0.1°C in the range of -20°C~85°C.

‌Structural features‌
It consists of NTC chip, protective shell (metal/plastic), leads and terminals, and adopts double-layer encapsulation process to improve sealing and resistance to mechanical damage.
Flexible size (minimum diameter 0.01 tum), support customized design.

Advantages:
NTC thermistors are known for their high sensitivity to temperature changes, compact size, and cost-effectiveness.

Typer:
NTC thermistors come in various forms, including chip, disk, and lugged versions, with each form having different advantages and applications.

Ii. Typical application scenarios‌
‌Consumer electronics and home appliances‌
Temperature feedback control of air conditioners and refrigerators; water heater anti-dry burning protection; washing machine water temperature monitoring.
‌New energy vehicles and energy storage‌
Battery pack temperature monitoring, motor overheating protection (high temperature resistant packaging and forced heat dissipation design are required).
‌Industrial control‌
Injection molding machine temperature control, heating furnace temperature calibration, power supply equipment overheating protection.
‌Medical equipment‌
Ventilator airflow temperature monitoring, dialysis equipment liquid temperature control, digital thermometer.
‌Other fields‌
Liquid level detection (oil tank oil level alarm), circuit temperature compensation (offsetting transistor drift).

‌III. Selection Guide‌

Factors Reference points
‌Temperature range‌ -50℃~150℃ general purpose; >150℃ requires special packaging (such as glass sealing).
Accuracy requirements For high-precision scenarios, select models with B value consistency within ±1% and R25 tolerance ±1% (such as MF53 series).
‌Environmental adaptability‌ For humid/corrosive environments, use stainless steel waterproof packaging (such as 10K3435 probe); anti-bending leads are required in vibration situations.
‌Response speed‌ When fast response is required, select a model with a thermal time constant of <5s.
‌Circuit matching‌ Select the R25 value according to the system impedance (such as 10kΩ is commonly used in 5V systems).

Iv. Technology Evolution Direction‌

‌Material Innovation‌: Gold electrode chips improve high temperature stability (>200℃).
‌Integration‌: Combined with wireless transmission module to achieve remote monitoring of the Internet of Things.
‌Heat Dissipation Optimization‌: Patented heat dissipation structure helps electric vehicle motors operate reliably in high temperature environments.

Notera: NTC sensors should be avoided in ultra-low temperature (<-50℃) or ultra-high temperature (>300℃) scenarios. For such conditions, it is recommended to use thermocouples (type K) or RTD410.