Thermoelectric transfer difference of thermal converters measured with a Josephson source

We have measured the thermoelectric transfer difference of two thermal voltage converters using a Josephson source and compared the results to similar measurements made with a conventional semiconductor source. Both sources use the fast reversed dc method. The Josephson source is an array of 16 384 superconductor-normal-superconductor Josephson junctions that is rapidly switched between voltage states of +0.5, 0, and -0.5 V. A marginally significant difference is detected between measurements with the two different sources.