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A portable system for measuring water temperature, conductivity, dissolved oxygen, light attenuation and depth of sampling
Author(s) -
BENHAM D. G.,
GEORGE D. G.
Publication year - 1981
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.1981.tb01277.x
Subject(s) - conductivity , attenuation , resistor , electronic circuit , environmental science , chart , materials science , analytical chemistry (journal) , voltage , electrical engineering , chemistry , optics , environmental chemistry , engineering , physics , statistics , mathematics
SUMMARY. This paper describes the design, construction and testing of a portable monitoring system capable of measuring water temperature, conductivity, dissolved oxygen, light attenuation and depth of operation. The unit is powered by rechargeable batteries and can be used to provide instantaneous readings or continuous records of each variable when used with a suitable chart recorder. Circuits for measuring conductivity and light‐ratio are of a novel design. The conductivity circuit measures conductance by the voltage drop across a low‐value resistor connected in series with the conductivity cell. The light‐ratio circuit measures light intensities by digitizing signals from two photocells and comparing their ratios over short periods of time. The paper includes examples of results obtained with the instrument in a wide range of applications and compares the performance of the Mackereth oxygen electrode with, and without, a small water‐circulating attachment.