Magnetic Balance for Teaching Metrology Concepts in Electrical Engineering

Abstract

In this paper a successful and inexpensive laboratory exercise is presented for explaining basic metrology concepts (reference value, standard, measuring error, traceability of measurement, measuring uncertainty) to undergraduate students of electrical engineering. For a better understanding, a common mass measurement was used. Mass of weights was measured by using a modified audio speaker as a weight balance, working on the principle of electromagnetic levitation. Speaker-balance measuring range was 10 g to 1000 g, with relative uncertainty of 3%. Students could learn about problems of the definition of the kilogram, about mass measurements and balances, repeatability of measurements, uncertainty budget calculations, and common measuring uncertainty contributions.