Induction Cooker Temperature Sensor

The following is the core technology analysis and maintenance guide of the induction cooker temperature sensor:
I. Core type and functional positioning

Sensor type	‌Installation location‌	‌Core function‌	Typical parameters
Stove surface temperature sensor	Under the ceramic panel/center of the stove	Monitor the bottom temperature of the pot to prevent dry burning and overheating protection	100KΩ（25℃）
IGBT temperature sensor	Surface of power tube heat sink	Real-time monitoring of IGBT operating temperature, triggering overheating protection	100KΩ±5%

Opmerking:
Induction cookers generally use NTC thermistors (temperature ↑ resistance ↓), and the packaging form is mainly epoxy resin, and some high-temperature models use glass seals.

II. Fault characteristics and detection methods

Parameters	‌Requirements‌	Notes
Resistance accuracy	±1%~±3%（25℃）	Deviation >±5% requires immediate replacement
Response time	<3 seconden (oil medium)	Glass-sealed models are suitable for environments >150℃
‌Packaging form‌	Big round head/water drop shape (Ø2.5~5mm)	Thermal grease must be filled during installation to ensure fit‌

‌Typical fault manifestations‌
Heating abnormality: The temperature of the pot is out of control (too high or too low);
Frequent shutdown: Overheat protection is triggered by mistake and the machine shuts down automatically;
Display error: The temperature value jumps or does not match the actual measurement.

‌Test steps‌
mermaid Copy Code
graph TB
A[Fault phenomenon] –> B[Measure resistance at room temperature with power off]
B — 100K±5KΩ normal –> C[Heating test]
B — Resistance ∞ or 0 –> D[Replace sensor]:ml-citation{ref=”2,8″ data=”citationList”}
C — Resistance decreases with temperature rise –> E[Line/mainboard failure]:ml-citation{ref=”8″ data=”citationList”}
C — Resistance unchanged –> D

‌Practical tips‌: Bake the sensor head with a lighter, and the normal resistance should drop from 100KΩ to below 10KΩ.

III. Technological evolution and new solutions

‌Limitations of traditional NTC solutions‌
Indirect temperature measurement: heat conduction through the ceramic panel, there is a response delay (over 1-2 seconden);
Accuracy deviation: ±3℃~5℃, affecting low-temperature cooking control

‌Infrared penetration technology breakthrough‌
‌MLX90617 chip‌: Directly penetrate the ceramic panel to detect the temperature of the bottom of the pot, with an accuracy of ±0.5℃;
Dual sensor collaboration: infrared probe + auxiliary sensor eliminates glass radiation interference.

Iv. Selection and replacement specifications

Supply chain reference‌:
General model (MF58): YAXUN Electronics $0.12~0.7/piece (100KΩ);
Infrared solution: Melexis MLX90617 chip needs to be customized.

V. Failure prevention measures
‌Avoid mechanical damage‌: Lead bending angle ＞90° is prone to breakage;
‌Regular dust cleaning‌: Oil accumulation affects heat conduction efficiency;
‌Voltage protection‌: Abnormal comparator LM339 will misjudge the temperature signal.

Attachment: ‌NTC resistance-temperature quick check table‌
‌Temperature‌ ‌100K sensor resistance