Watt

Abstract: In this book the author focuses on the 11 months following the Munich conference in September 1938, and chronicles the events that led to world war. His approach is through the eyes of the leaders of all the powers involved, drawing on official records, private papers, reminiscences and biographies of the politicians, soldiers, diplomatists and others who took part in the processes which led to war.

Abstract: To reach uncertainties in the region of 1 part in 108 a moving-coil watt balance not only requires the accurate measurement of voltage, resistance, velocity, mass and the acceleration due to gravity but, in addition, requires the apparatus to be adjusted correctly to minimize the second order effects which can reduce the accuracy of the measurement. This paper collects together the alignment and correction techniques that have been developed at NPL over many years and are required to minimize the uncertainty of the measurement. Some of these techniques are applicable to all watt balances, whilst a few are specific to watt balances that employ a conventional beam balance to support a circular coil in a radial magnetic field, such as the NPL Mark II watt balance, now known as the NRC watt balance.