Monday, September 24, 2012
Composition and principle of hygrometer
Hygrometer constituted by two identical thermometers. Which a dry bulb thermometer hygrometer, the other for the wet bulb thermometer.Relative humidity hygrometer completely Principle: As the wet bulb thermometer temperature bubble wrapped cotton yarn, cotton yarn immersed in the bottom of the water, the water evaporates leaving the wet bulb thermometer shows the temperature is always lower than the number of dry bulb thermometer shows the temperature number (temperature) the temperature difference with the speed of water evaporation (ie, when the relative humidity) for. According to two thermometer readings, from the table or curve can be found on the air relative humidity.
Digital thermometer using temperature-sensitive element which is the temperature sensor (such as platinum resistance, thermocouple, semiconductor, thermal resistance, etc.), the temperature change into electrical signals, such as voltage and current changes, based on the use of digital thermometer different sensors, AD converter circuit, and the different processing units, its accuracy, stability, temperature range, etc. are different.
Clinical Digital Thermometer measuring instruments and sub-degree level of accuracy values? name of instrument accuracy class division value?(Celsius).Bimetal thermometers 1,1.5,2.5 0.5 to 20.Pressure thermometer 1,1.5,2.5 0.5 to 20.Glass thermometer liquid 0.1 ~ 0.5 ~ 2.5 10.Thermal resistance of 0.5 ~ 31 ~ 10.Thermocouple 0.5 to 15 ~ 20.Optical pyrometer 1 ~ 1.5 5 ~ 20.Radiation thermometer (thermopile) 1.5 5 20.Part of the radiation thermometer 1 ~ 1.5 1 ~ 20.Colorimetric thermometer 1 to 1.5.