On the definition of DC in resistance measurements

This paper considers the problem of defining measurement conditions that approximate `DC´ for resistance standards. A recent on-site comparison between the BIPM and the PTB highlighted this difficulty in dealing with Peltier heating in 1 Ω standards, but it is a general problem with a variety of causes. We aim to draw attention to this potential source of error and to open a discussion on how to mitigate the problems by improved definitions of the measurand.