The Main Classification Of Thermometer

With the development of science and technology and the needs of modern industrial technology, the temperature measurement technology has also been continuously improved and improved. As the temperature measurement range becomes wider and wider, according to different requirements, different temperature measurement instruments are manufactured. Here are a few.

● Rotary thermometer

The rotary thermometer is made of a rolled bimetal. The bimetal is fixed at one end and connected to a pointer at the other end. Due to the different degree of expansion of the two metal sheets, the bimetal sheet curls differently at different temperatures, and the pointer then points to different positions on the dial. The temperature can be known from the reading on the dial.

● Semiconductor thermometer

The resistance change of a semiconductor is different from that of a metal. When the temperature increases, the resistance decreases, and the change range is larger. Therefore, a small amount of temperature change can also cause a significant change in the resistance. The manufactured thermometer has a higher precision and is often called a temperature sensor.

● Thermocouple thermometer

A thermocouple thermometer consists of a sensitive voltmeter connected to two different metals. At different temperatures, metal contacts will produce different potential differences between the two ends of the metal. The potential difference is so small that it requires a sensitive voltmeter to measure it. From the reading of the voltmeter, you can know what the temperature is.

● Optical pyrometer

If the temperature of an object is high enough to emit a large amount of visible light, the temperature can be determined by measuring the amount of its thermal radiation. This type of thermometer is an optical thermometer. This thermometer is mainly made of a telescope with a red filter and a set of circuits with a small bulb, an ammeter and a variable resistor. Before use, establish the relationship between the temperature corresponding to the different brightness of the filament and the reading on the galvanometer. When using, align the telescope with the object to be measured and adjust the resistance so that the light bulb has the same brightness as the object to be measured. At this time, the temperature of the object to be measured can be read from the galvanometer.

● LCD thermometer

Liquid crystals made with different formulations have different phase transition temperatures. When the phase transition occurs, the optical properties of the liquid crystal also change, making the liquid crystal appear discolored. If liquid crystals with different phase transition temperatures are coated on a piece of paper, the temperature can be known from the change in the color of the liquid crystal. The advantage of this thermometer is that it is easy to read, but the disadvantage is insufficient accuracy. It is often used in ornamental fish tanks to indicate the water temperature.

● Digital thermometer

Digital thermometer uses a temperature sensor to convert (temperature) into a digital signal, and then displays the temperature in digital form through a display (such as LCD, digital tube, LED matrix, etc.). It can quickly and accurately measure the highest value of human body temperature. Compared with mercury thermometers, it has the advantages of convenient reading of numbers, short measurement time, high measurement accuracy, memorization, and prompt sounds. Especially, digital thermometers do not contain mercury and are harmless to the human body and the surrounding environment. They are especially suitable for hospitals and families.

● Mercury thermometer

The spilled mercury must be collected immediately with a dropper and a brush, and covered with water (preferably with glycerin), and then sprinkled with sulfur powder on the polluted area. It can be cleaned after there is no liquid (usually about one week).