High performance conductivity monitoring instrument with pulsating sensor

We present an unconventional but high performance pulsating conductivity monitoring instrument constructed by using a new class of sensor, viz., pulsating sensor developed in house. The design consists of a special type of logic gate oscillator (LGO) powered by 5 V direct current (dc). The conductivity cell constitutes a part of LGO. In this conductivity meter the primary signal generated from the sensor is directly in digital domain which is easily transmitted either to a personal computer or to a stand-alone embedded system. Hence it reduces the hardware components making the instrumentation highly simplified. The output of the instrument is pulse frequency which is directly related to the conductivity of solution used for measurement. The relation between pulse frequency and conductivity is determined following a multipoint calibration technique developed in our laboratory using a series of KCl standards. The performance of the instrument is demonstrated with a few examples which reveal the diverse application of this new approach of measurement technique. (C) 2010 American Institute of Physics. [doi:10.1063/1.3449552]