A New Generation of Multijunction Thermal Current Converters

Multijunction thermal converters (MJTCs) are in routine use at the National Institute of Standards and Technology for ac voltage measurements at levels from 250 mV to 60 V, over the frequency range from 10 Hz to 100 MHz. The use of these devices has resulted in reductions in uncertainty of as much as 60% at some points in the voltage parameter space. A new generation of MJTCs, optimized for ac current metrology, promises to accomplish much the same results over the parameter space for ac current transfer difference. This paper describes the motivation for this project, the new designs under consideration, and the results of the work.