It is shown that in thermocouples consisting of arms in the form of coaxialNandPdisks in which the current flow is radial, two regions must be distinguished. If theNandPdisks are narrowly spaced, then the temperature difference between the hot and cold junctions tends to infinity. If, on the other hand, the disks are widely spaced, then the maximum temperature difference is the same as that of a linear couple.