Modification of a NIST based 1 V Josephson voltage standard system to accept a PTB 10 V Josephson array

A 1 V Josephson Voltage Standard (JVS) has been in periodic operation at the National Metrology Laboratory (NML) of South Africa since February 1993. This system is based on the design by the National Institute of Standards and Technology (NIST), USA, which supplied the NML with a 1 V array free of charge. The NIST also supplied helpful comments throughout the commissioning period. In September of 1995, the Physikalische-Technische Bundesanstalt (PTB), Germany, donated a 10 V array to the NML. This paper describes the system modifications necessary to enable the NML system to operate with the 10 V PTB array