Design and Development of a Portable Conductivity Measurement Instrument as an Aid for Teaching Power Electronics at Undergraduate Level

Abstract

The paper outlines the design and development of a conductivity measurement instrument for conductive sheets or plates. This instrument uses a four-point Kelvin connection to measure the resistance in range of a few milliohm. The voltage drop in the sample is amplified using an instrumentation amplifier. The instrument is battery operated, and hence, portable. The required signals are digitally filtered on a mi-crocontroller, which is also used for displaying the measured quantities over a dedicated display. The instrument's suitability for estimation of conductivity, by measuring dc-resistances of the sample, is demonstrated experimentally within 5% accuracy. The developed instrument makes extensive use of off-the-shelf electronic modules, most of which are power-electronic modules. To name a few, two boost converters, one buck converter, and a battery charging and protection module are based on semiconductor devices operating in switched-mode. Undertaking this development as a project would provide good exposure to the entering undergraduates towards the direct application of power-electronics in efficiency concerned applications, such as this battery-operated instrument.