What kind of thermometer can measure low temperature?

Generally bimetallic thermometer ( The pointer thermometer) Minimum range minus 50 c, if lower than the temperature to choose other types, such as electronic, or mercury and so on, in short to know the temperature of the reaction liquid to be tested. Usually choose the range of the thermometer measured temperature to include, for example, the minimum minus 20 c, it will have to choose a below contains below minus 20 c, at least is minus 30 c, it will be relatively accurate. According to you need test, bimetallic thermometer and electronic thermometer is right choice. Bimetallic thermometer temperature sensing element is two pieces of expansion system made of different metal stitch welding together. Bimetallic strip after heat due to the expansion of the two sheet metal bending length is not the same. The length and width of the linear expansion of the higher the temperature the greater the difference, thus draws the greater the bending Angle, the bimetallic strip are made into spiral tube, this is the working principle of bimetallic thermometer. Bimetallic thermometers use areas: industrial, petroleum, chemical, heating system, pipeline, water heater, incubator, etc. Electronic thermometer is the use of temperature sensor output signal, directly to output digital signals or electric current signal, Analog signal) Into the inside integrated circuits can be recognition of digital signal, and then through the display ( Such as LCD, digital tube, LED matrix, etc. ) Displayed in the form of digital temperature, can easily read values. Electronic thermometer generally used at home, the tank with a thermometer, can let people intuitively know you want to know the temperature, intuitive and convenient. Thermal tape line, line length is usually 1. Do line length 2 meters, can according to demand. When a distance or object to be tested in an airtight space, electronic thermometer with line to solve this problem, such as refrigerator, you don't have to walk into the inside of the refrigerator can view the temperature. Measuring the temperature of the liquid and gas, for remote reading of temperature or the temperature of the confined space.