Thermistor structure and classification

　　Thermistors are mainly composed of thermal probes, leads and shells. Thermistors are generally made of two-terminal devices, but there are also three-terminal or four-terminal ones. Two-terminal and three-terminal devices are direct thermal, that is, power is obtained directly from the circuit. Four-terminal devices are bypass-heated. According to different requirements, the thermal resistance can be made into different shapes and structures.

　　The positive temperature coefficient thermistor is made of barium titanate (BATIO3), strontium (Sr), zirconium (Zr) and other materials, and is a direct thermal thermistor. The resistance value is proportional to the temperature change, that is, the resistance value increases when the temperature increases. At room temperature, its resistance value is small, only a few ohms to tens of ohms; when the current flowing through it exceeds the rated value, its resistance value can rapidly increase to hundreds of ohms to several thousand ohms in a few seconds The above are widely used in color TV degaussing circuits, refrigerator compressor startup circuits and overheating or overcurrent protection circuits, and can also be used in electric mosquito repellents and hair curlers, electric heating pads, heaters and other small appliances.

　　Negative temperature coefficient thermistors are made of manganese (Mn), cobalt (Co), nickel (N), copper (Cu), aluminum (Al) and other metal oxides (with semiconductor properties) or silicon carbide (SiC) and other materials. Made of ceramic technology. Its resistance value is inversely proportional to the temperature change, that is, when the temperature rises, the resistance value decreases accordingly. It is widely used in refrigerators, air conditioners, microwave ovens, electric ovens, copiers, printers and other home appliances and office products for temperature detection. , temperature compensation, temperature control, microwave power measurement and voltage regulator control.

　　Classification of thermistors

　　According to the structure and shape, it is divided into a variety of thermistors such as disc-shaped (sheet-shaped), cylindrical (column-shaped), circle-shaped (washer-shaped) and so on.

　　According to the sensitivity of temperature change, it is divided into high-sensitivity (mutant) and low-sensitivity (slowly) thermistors.

　　According to the heating method, it is divided into direct heating thermistor and side heating thermistor.

　　According to the characteristics of temperature change (temperature change), it is divided into positive temperature coefficient (PTC) and negative positive temperature coefficient (NTC) thermistors.

Read recommendations:

NTC9251.motion detector

The application of NTC thermistor in automation equipment.Automatic machine mirror

Φ20mm size with glass case

PIR Lens 7805

PND103F3950FTR310 NTC Thermistor 10K 1% 3950