CONVERTER WITH TEMPERATURE OFFSET FOR CAPACITATIVE HUMIDITY SENSOR

摘要

The converter is used in devices for the measurement and monitoring of the relative humidity of gases, especially of the atmospheric air. It is sensitive and accurate in a wide temperature and humidity range, makes linear convertor, has differential voltage output and simplified electrical circuitry. The converter consists of a multivibrator with two symmetric outputs each having an integration RC-circuit on each of the outputs. The multivibrator is built of two identical transmitors T1 and T2, in the time-setting RC-group of one of them a capacitative sensor for humidity Cx is included, and in the time-setting group of the other one an analogical sensor Ct is connected, the humidity sensitive layer (4) of which is insulated from direct contact with the environment by means of a vacuum applied layer of a precious metal (5), impermeable for the water vapours.