| Popis: |
In 1981 the decision was taken to establish a National Standard for humidity measurement at the National Physical Laboratory, England. The instrument system consists of two major parts, the Precision Humidity Generator and the Primary Gravimetric Hygrometer (PGH). The latter has been developed by Sira Ltd under a contract from NPL (ref. 1). In this paper, following a concise description of the principles of the Primary Gravimetric Hygrometer, aspects of the vacuum microbalance system are discussed. |
