What is the percentage of humidity in the electronic thermometer and hygrometer? What is the principle of measurement? Is it necessary to calibrated it for a period of time, or no need to be calibrated?

 

 

1) Relative humidity % RH (Relative Humidity), usually expressed as a percentage (%), ie (the ratio of the actual water vapor content in the atmosphere to the saturated water vapor content at that temperature and at the same pressure). Its definition is as follows:
Relative humidity = (actual water vapor weight / saturated water weight at the same temperature and the same pressure) × 100%
Since the weight of water vapor in the air is quite small, we use the vapor pressure to represent the weight of the water vapor (temperature, when the volume is fixed, the air pressure is proportional to the weight of the gas).
Because the saturated vapor pressure of water vapor increases with the increase of temperature
, so the relative humidity is the same, the temperature
The water vapor weight in the high air is higher than when the temperature is low. We usually
The air is very wet, which means that the relative humidity RH is large.
Due point temperature is called dew point. It means that the air is kept at the same pressure and water vapor content. If the temperature is gradually lowered, the water vapor will reach saturation and begin to condense into water droplets (dew beads).
The temperature at the time. Therefore, when the relative humidity is 100%, it means in the air.
The water vapor is saturated and the temperature is the same as the dew point; therefore, if the water vapor is not saturated and the relative humidity is less than 100%, the temperature at that time must be higher than the temperature at the dew point.
2) If the electronic thermometer and hygrometer is a low price (NT$ 1~ 3000), it is usually made in large quantities by the integrated circuit Chip IC. Because of the price difference, the high temperature variable temperature resistor cannot be used, so it cannot be adjusted. 3) The sensor of the general hygrometer can only be used in general environment. For example, when the temperature is > 50 ° C or the temperature is lower than 10 ° C, the SENSOR sensor is easily damaged. Be careful when using it. Therefore, if there is any abnormality, or when it is one year old (electronic parts will age with time), it needs to be sent immediately. 4) How to find the abnormality of the thermometer and hygrometer:
The temperature can be checked by mercury thermometer or by the school traceability laboratory. The humidity can only be used. The humidity is usually about 70 ~ 95% in rainy days, and the humidity in sunny days is about 40 ~ 70% (higher in summer, dry in winter), or Compare with the hygrometer sent to the school's traceability laboratory. Life application: Dry air in winter, throat is easy to dry and inflamed. Air humidity between 45 and 65% is the most comfortable and pleasant; If the indoor humidity is too low, you can put a glass of water, add a few drops of fragrance to make the room full of fragrance, or buy an air humidifier to increase the humidity. Conversely, if the air humidity is too high, the item is prone to mold, people are prone to illness, at this time, dehumidifier It can be used