Humidity seems to be a very simple physical quantity, but in fact, the physico-chemical theory and calculation of humidity design are quite complex. Humidity measurement is also an important scientific research direction in the field of metrology. Today we will take a look at what are the common humidity measurement methods. Common humidity measurement methods are: dynamic method (double pressure method, double temperature method, shunt method), static method (saturated salt method, sulfuric acid method), dew point method, wet and dry bulb method and electronic sensor method. Method 1: Dynamic method. The double pressure method and the double temperature method are based on the thermodynamic principle of P, V, and T equilibrium, and the equilibrium time is longer, and the split method is based on the precise mixing of absolute moisture and absolute dry air. Due to the use of modern measurement and control means, these equipment can be quite precise, but because the equipment is complex, expensive, time-consuming and labor-intensive operation, mainly used as standard measurement, its measurement accuracy can reach more than ±2%RH. Method 2: Static method. The saturated salt method in the static method is a common method in humidity measurement, which is simple and easy to implement. However, the saturated salt method has strict requirements for the balance of liquid and gas phases, and has high requirements for the stability of ambient temperature. It takes a long time to equilibrate and a longer time to use it, and it takes longer for low wet spots. Especially when the difference between the indoor humidity and the humidity in the bottle is large, it needs to be balanced for 6~8 hours each time it is opened. Method 3: Dew point method. The dew point method is a measurement of the temperature at which moist air reaches saturation and is a direct result of thermodynamics, with high accuracy and a wide measurement range. Precision dew point meters for metrology can achieve an accuracy of ±0.2°C or more. However, chilled mirror dew point meters with modern optical-electric principles are expensive and are often used in conjunction with standard humidity generators. Method 4: Wet and dry bulb method. The wet and dry bulb method is a humidity measurement method invented in the 18th century. It has a long history and is widely used. The psychrometer-bulb method is an indirect method that uses the psychrometer-bulb equation to calculate the humidity value, which is conditional: the wind speed must be more than 2.5 m/s in the vicinity of the wet bulb. The common wet and dry bulb thermometer simplifies this condition, so its accuracy is only 5~7%RH, and the wet and dry bulb does not belong to the static method, do not simply think that as long as the measurement accuracy of the two thermometers is improved, the measurement accuracy of the hygrometer is improved. Method 5: Electronic humidity sensor method Electronic humidity sensor products and humidity measurement belong to the industry that emerged in the 90s, and in recent years, great progress has been made in the field of humidity sensor research and development at home and abroad. Temperature and humidity transmitters are products that use moisture-sensitive elements for industrial automation measurement. Temperature and humidity transmitters are widely used in indoor, outdoor, ventilation ducts, heating and air conditioning systems, constant temperature and humidity controllers/boxes and other working conditions of humidity measurement. At the same time, it has the characteristics of good long-term stability, wide working temperature range, accurate measurement and high protection level. Temperature and humidity transmitters are already indispensable products in the field of instrumentation. If you have any questions about product consultation, product customization, agency, technical inquiry, quotation, etc., please contact Xingyi: 400-600-4496!