An intelligent voltage standard

Voltage standards based on solid-state references are now commercially available with drifts of the order of a few parts per million per year. In order to achieve a good measure of confidence when dealing with these stabilities, it is usual to operate a large group of standards which may be readily intercompared. Thus any anomaly in one member of the group can be detected, and appropriate action taken. The Intelligent Voltage Standard (IVS) performs the task of inter-comparing a group of eight Zener diodes under computer control. It uses ordinary commercial components and the controller is a slightly modified simple microcomputer. It presents information to the user about any anomoly in the group of Zeners that has been detected and recommendations for action. The computer program has data on the Zener “aging” rates and so presents the user with an expected value for the output of the standard on any day that it is used.