Optimized Rc-Timing Technique for Accurate Measurement of Minute Capacitance Changes

Abstract

This paper presents a technique for accurate measurement of small capacitive changes. This is based on selecting the most linear part of the curve obtained by charging through a known resistor value the capacitive element undergoing changes as a result of sugar level. This measurement is part of the design of a system for measuring blood glucose content non-invasively. The technique is based on measuring ultralow glucose levels in the blood as capacitive changes converted into RC timing constant optimized using a circuit set to trigger at an appropriate time activating a counter. The measured data is captured instant later, selecting the most linear part of the charging curve. The results thus obtained are compared with the ones obtained through RC-timing standard technique. The result reported here are with a remarkable low error of about 2.25% when compared with 11.78% by the standard RC-timing technique