Ten-volt Josephson voltage standard at the ETL

A voltage standard system using a 10 V Josephson junction array has been developed. The uncertainty is 0.6/spl times/10/sup -8/ for measurement of the 10 V output of a Zener diode reference standard. A comparison of the 10 V array system with the conventional 10 V measurement system composed of a 1 V array and a voltage divider was performed through measurements of a 10 V output of a Zener. The result agreed within the uncertainty (2/spl times/10/sup -8/) of the comparison. The 10 V output voltages of a Zener reference standard are measured consecutively by the 10 V array system.