Application of thermistor sensors in refrigerators

Refrigerators have become one of the must-have household appliances for many Chinese families. With the different needs of people, the styles of refrigerators are diversified and the functions are becoming more and more abundant. Of course. The intelligence of refrigerators is inseparable from the support of sensors. Only intelligent sensors can achieve intelligent refrigerators.

Through the improvement of the refrigeration system of direct cooling refrigerators and the use of temperature sensor technology, dual temperature and dual control of refrigerators are realized. In this way, refrigerators can quickly and reasonably adjust the cooling capacity according to the changes in usage conditions, and the energy-saving effect is good.
At present, temperature sensor products have developed from analog integrated temperature sensors to the application stage of intelligent digital temperature sensors. The characteristics of intelligent temperature sensors are: they can output temperature data and related temperature sensing quantities. They are suitable for various sensors, and realize the sensing function through software on the basis of hardware.

For example, in a certain type of refrigerator, the temperature sensing element of its built-in thermistor temperature sensor is a thermistor. How does it automatically control the temperature? First, place it in an appropriate position in the refrigerator. When the temperature inside the box changes by 1-2°C, the resistance of the thermistor changes accordingly. Then, after this change is amplified, it drives the power-off device to operate, controls the start and stop of the compressor motor, and realizes automatic control of the temperature inside the box.

Principle of thermistor temperature sensor in refrigerator

The temperature sensor mainly uses a thermistor with a negative temperature coefficient. When the temperature changes greatly, the resistance of the thermistor also changes. When the temperature rises, the resistance decreases; when the temperature decreases, the resistance increases.

Nowadays, some new refrigerators on the market have four types of temperature sensors:

(1) The main function of the refrigerator compartment sensor is to detect whether the set room temperature has been reached to determine whether the refrigerator is turned on or off.

(2) The main function of the freezer compartment temperature sensor is to detect the freezer compartment evaporator temperature to control defrosting.

(3) The main function of the defrost sensor is to detect the freezer compartment temperature to control the start and stop of the defrost operation.

(4) Inverter series refrigerators also have exhaust and intake temperature sensors. The main function of the exhaust and intake temperature sensors is to detect the temperature of the compressor's intake and exhaust ports. When a temperature sensor fails, the machine will display the corresponding fault code through the self-test function to determine which sensor has failed.

Detection method of thermistor temperature sensor in refrigerator

Common faults of temperature sensors include open circuit, short circuit and resistance value that does not change with temperature. You can use a multimeter to measure directly, and then judge the quality of the temperature sensor by comparison. If necessary, the temperature sensor or the thermistor in it needs to be replaced in time.