Thermometers use a series of physical reactions to measure temperature.
• Mercury-in-glass thermometer
• Alcohol-in-glass thermometer
• Electrical resistance thermometer
• Infra-red thermometer
• Thermistor Thermometer
• Thermocouple Thermometer
Mercury thermometer
A thermometer made of glass that contains a mercury bulb and a mercury column. The degree of increase of the mercury column depends on the degree of heating. The data that does not rise after rising to a certain scale is the correct temperature reading. “Mercury thermometer” can measure the temperature between -38°C and 357°C.
Due to the severe toxicity of mercury, it is not easy to find mercury thermometers on the market. For laboratory use only, thermometers with special functions can still be purchased. For example, the Precision 1/100 degree/°C thermometer used by the company.
Acohol thermometer
A thermometer made of glass containing an alcohol ball and an alcohol column, the alcohol in the alcohol column expands when heated. The degree of increase of the alcohol column depends on the degree of heating, and the measurable temperature is from -115°C to 110°C. Compared with mercury thermometers, alcohol thermometers respond slower to temperature changes. Generally, alcohol will be dyed red, but alcohol thermometers of other colors are also available.
Resistance thermometer
Also known as Resistance Temperature Detectors (RTDs), they are temperature sensors that use materials whose resistance varies with temperature. Because they are almost exclusively made of platinum, they are often called platinum resistance thermometers. They are slowly replacing thermocouples in many industrial applications below 600°C.
At present, the company’s product, BBW-6000 plasma thawing warming instrument, uses an alcohol thermometer as a physical thermometer.
Advantages and Limitations
• high precision
• low drift
• Wide application range
• Suitable for high precision applications
limit:
• RTDs are rarely used in industrial applications at temperatures above 660°C. At very low temperatures, such as below -270 °C (or 3K), the resistance has zero sensitivity and is therefore not practical.
• Platinum RTDs are less sensitive and have slower response times than thermistors.
infrared thermometer
Divided into fixed thermometers and handheld thermometers (forehead thermometers), it is a thermometer that uses the amount of infrared rays detected on the surface of an object to achieve temperature measurement. Because the greater the amount of infrared rays, the higher the temperature, so infrared rays can be used to measure temperature. The measurement range is generally within 400 °C, up to 3000 °C, and the measurement error is between 1 and 3%.
Infrared thermometers are usually equipped with a laser to help the user determine the measurement area.
advantage
• No direct contact with the DUT
• Can measure high temperature
• Fast reaction time
• Support multiple signal output
shortcoming
• Susceptible to surface reflections from objects.
• It can only measure the surface temperature of the object, and it is inconvenient to measure the inside of the object. Precautions
• The thermometer should be aimed vertically at the surface of the object to be measured.
• The 8-14um wavelength cannot be used for temperature measurement through glass
• Short wavelength through glass measurement
• Short wavelengths can be used to measure metal surface temperature
Thermistor Thermometer
It is a thermometer that can measure body temperature and room temperature. The resistance value changes with the change of temperature, and the change of volume with temperature is much larger than that of ordinary fixed resistance. The English “thermistor” of a thermistor is a portmanteau of the words Thermal (heat) and resistor (resistance).
Thermistors are a type of variable resistors and are widely used in various electronic components, such as inrush current limiters, temperature
Temperature sensors, resettable fuses, and self-adjusting heaters, etc.
Unlike resistance thermometers which use pure metals, the materials used in thermistors are usually ceramics or polymers. The two also have different temperature response properties, resistance thermometers are suitable for a larger temperature range; while thermistors usually achieve higher accuracy in a limited temperature range, usually -90°C ~ 130°C.
3 pcs thermistors are used inside FIW-1450 for temperature control and temperature protection.
Thermistor Thermometer
It is a widely used temperature sensor and is also used to convert thermal potential difference into potential difference. Thermocouples are cheap, easy to replace, do not need an external power supply during measurement, have standard interfaces, and have a large temperature range. The main limitation is accuracy, with systematic errors typically greater than 0.1°C.
