Quartz Planar Multijunction Thermal Converter as a New AC-DC Current Transfer Standard up to 1 MHz

Abstract

The new generation of PMJTCs on quartz membranes and on quartz crystal chips developed at the PTB results in new ac-dc current transfer standards for the current of 10 mA and the frequency range from 10 kHz to 1 MHz, accompanied with small uncertainties. For a PMJTC witth a heater resistance of 240 Q the uncertainties for frequencies up to 100 kHz are smaller than 1 ,A/A and up to 1 MHz they increase to 5 jiA/A (k=1). A model for the PMJTC has been developed which allows to calculate the ac-dc current transfer difference as well as the attributed uncertainties. The agreement of the simulation and the measurement were tested for high heater resistances of 700 Q and 240 Q, for which quite large acdc differences are calculated. The good agreement validates the model.