On summer nights, mosquitoes raged and stung people uneasy, but as long as the electric incense was plugged in, even though it was smokeless and tasteless, the mosquitoes flee one after another, and people can fall into their dreams without the need for mosquito nets. How does the electric mosquito coil have this magical power? It turns out that there is a piece of ceramic called positive temperature coefficient resistance ceramic, or PTC ceramic for short. Electric current passes through this ceramic to generate heat. When the temperature rises to the required temperature, its resistance can increase thousands to millions of times, so that the current through the ceramic sheet is reduced, and the ceramic sheet is maintained at the temperature required for the mosquito repellent to slowly evaporate. PTC ceramics can not only be energized to generate heat, but also can automatically control the temperature. The electric pattern incense is made by using this characteristic.
Ordinary ceramics used to make cups, plates and dishes are non-conductive insulators. Since the 1950s, scientists have discovered that metal oxide ceramics that are originally insulators, such as barium titanate, titanium dioxide, tin dioxide, and zinc oxide, can become conductive as long as they are mixed with small amounts of other metal oxides. Ability, their resistance is between insulators and metals, people call them semiconductor ceramics. The resistance of various semiconductor ceramics will change tens to millions of times with changes in environmental temperature, humidity, atmosphere, light intensity and applied voltage (they are called heat sensitive, humidity sensitive, gas sensitive, photosensitive , And voltage-sensitive ceramics), the use of these ceramics can be used to manufacture a variety of electronic devices to serve mankind.
The temperature sensor made of thermistor whose resistance changes with temperature can measure temperature. It has faster response and higher accuracy than other methods. The miniature temperature sensor is smaller than a grain of sesame. The thermometer made of this kind of sensor, A person's body temperature can be measured in a few seconds. There are many types of temperature measuring instruments made of thermal ceramics. They are not only used in temperature measurement and control in industrial and agricultural production, but also in the automatic temperature control of air conditioners and refrigerators in people's homes.
Utilizing the heat and temperature control characteristics of PTC ceramics, many household electric heating appliances, such as heaters, hair curlers, footwarmers, hand stoves, etc., can be manufactured. In recent years, people have coated semiconductor ceramic materials on glass, ceramics, enamel and other utensils, which are used to produce electric kettles, electric hot pots, electric water heaters, etc., compared with similar electric heaters that use electric heating wires as heating elements. The film heating element has the advantages of large heating area, uniform temperature, rapid heating, safety without open flame, and energy saving of 20-30%.
Poisoning accidents caused by gas leaks in the family happen from time to time, often causing the whole family to die! Traffic accidents caused by drunk driving are even more numerous, causing many deaths and injuries every year. The emergence of gas-sensitive ceramics can solve these problems. There are some oxide semiconductor ceramics, such as oxides of metals such as tin, zinc, titanium, and iron. Their resistance will change hundreds to tens of thousands of times with the concentration of various gases. Therefore, various gas sensors can be manufactured using these ceramics. People colloquially call them electronic noses. A gas alarm is now installed in the kitchen. Once there is a gas leak, it will automatically flash and buzz to warn people to take immediate measures. The ceramics whose resistance varies with the concentration of alcohol vapor can be used to make wine-sensitive sensors. The sensor is installed on the car's engine control circuit. If the driver drinks alcohol, the car can't start, which can prevent drunk driving and accidents.
A humidity sensor made of ceramic whose resistance changes with air humidity can measure and control atmospheric humidity. The air conditioner equipped with this kind of sensor not only warms in winter and cool in summer, but also maintains the most comfortable humidity for human beings. You will neither have the dampness of Huangmeitian nor the dryness of cold winter. A microwave oven equipped with a humidity sensor can fully automate the cooking of dishes. In addition, the clothes dryer in your home can make the clothes dry completely without scorching, all controlled by the humidity sensor.
Semiconductor ceramics are making more and more contributions to the comfort and happiness of our lives! Mingrui Ceramics is a professional manufacturer of semiconductor ceramic products. If you have any questions about semiconductor ceramic products, please feel free to contact us.
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