A Capacitor-Type Rain Gauge with dc Output and Improved Flow Characteristics

Abstract

A rain gauge for continuously measuring rainfall rates in the range 0–800 mm/h is described. The collected rain water is channeled to flow through a capacitor which constitutes one arm of an RC bridge. The ac voltage across the bridge is processed to give a dc output which is nearly linearly proportional to rainfall rate. This gauge is an improved version of the one discussed by R. A. Semplak [Rev. Sci. Instrum. 37, 1554 (1966)]; low as well as high rain rates can be measured accurately. The output incorporates a time constant which can be switched in to smooth rapid fluctuations in rain rate. An example of an actual rainmeasurement is given.