NONCONTACT MULTI-SENSING TECHNIQUE FOR THE PRECISE MEASUREMENT OF CONCENTRATION OF ELECTROLYTIC SOLUTION

A new approach for the precise measurement of low concentration of ele ctrolytic solutions using multi-sensing technique is presented in this paper. For achieving this multi-functional sensing function, a novel structure is proposed for the multi-functional sensor. Two sensing fun ctions, namely, the inductive and the capacitive sensing functions, ca n be realized by this sensor. From the two types of sensing two databa ses are created and then the unknown concentration is precisely determ ined by comparing with the two databases. Experimental results using t he sensor on various solutions of low concentration of NaCl, K2SO4 and Pb(NO3)(2) electrolytes show distinct response to various concentrati ons as well as to different solutions. A concentration as low as 1 ppm of solution is possible to measure by this sensor. (C) 1998 Elsevier Science S.A. All rights reserved.