A Lecture on Accurate Inductive Voltage Dividers

The United States Naval Academy is an undergraduate school with a successful engineering program. An underlying philosophy in the Systems Engineering Department is to emphasize hands-on experience while maintaining a solid theoretical background. To realize this principle, both teachers and students face many challenges. In this paper an attempt is made to teach students how to build a very accurate ac voltage divider with an uncertainty better than a partper-million. This implies building a transformer-based divider. The idea is to bridge the gap between the state-of-the-art achievements in modern research and the undergraduate level of expertise. Several years ago a group of midshipmen built a voltage divider for a critical point experiment that was conducted in collaboration with a National Institute of Standards and Technology and NASA space shuttle program. In order for the students to be able to build a good transformer lots of coaching took place. This lecture is intended to introduce an engineering student into the art of precise voltage-ratio measurements.